Unless your planning to add 250 -300 sq ft of sail area to your your TI (if you have a TI), you don't need to modify or add anything at all to your boat. Many people have added just the Hobie kayak sails to their AI/TI's with no issues. I think one mis-conception everyone has about adding just a jib to you Adventure type boat is that it will increase your speed greatly, it doesn't, it will add maybe 1 mph to your top speed and that's it (hardly worth the effort for that). However the reason I always fly a jib is the jib allows you to sail closer to the wind, instead of 45 deg off the wind you can get closer (maybe 30-35 deg) upwind. As long as the jib is under around 25 sq ft (maybe a little more on a TI), most everything will still work fine. If you fly the jib in a batwing configuration on downwind runs you can increase the downwind performance slightly (without having to add a giant spinnaker (which also has it's own issues, and adds much complexity to the boat for no real reason).
You also have to keep in mind by adding a standard jib you are also increasing the lateral force on the boat (the force trying to tip you over), so as winds increase you have to furl the sails in earlier or run the risk of burying the AMA's or tipping over.
I don't know much about the AI's, as I've never owned one so I can't comment on them. But on my TI if I didn't have the bowsprit (I didn't used to have that stuff) and I try to go on a strong downwind (> 15mph winds) flying 260 sq ft of sail, because the main sail is mounted so far forward the bow of the boat completely submerges (what I used to call nautilus mode). Basically your sails are generating about 50 hp and the bow goes underwater and just stays there until you release the sails (and I would never do that ( LOL)), I would just fly along like a submarine. Before adding the bow sprit I had hydrofoils mounted under the boat to create some lift to get the bow to raise, but later on figured out by angling the fore sails to an extreme angle so they can also create lift as well as forward force, this solved the diving problem and I was able to remove the foils about 3 yrs ago and haven't had them back on since except when I go out in extreme winds and want to foil around (just screwing around). But the winds have to be over 15-20 mph for all my foiling stuff to work correctly, and it can get very dangerous, so I don't do it much. Before attempting any of this extreme stuff it's probably a pretty good idea to massively harden the TI for offshore use and rough conditions as the AI/TI only has an EC 'C' rating and is not suitable for offshore use, if you want to do that stuff get something else.
I don't pretend to understand the engineering, but I do have eyes, with my original setup with no bowsprit and no bow brace flying 260 sq ft of sail, I could watch the bow flex up and down 6 inches, and I would take on easily 5 gallons of water into the hull in under 30 minutes in not super extreme conditions.
Here is a video of the bow in light conditions with the first version of the bow sprit, it was designed as a truss to prevent side to side stress, and the forward pulling stress from the huge 135 sq ft spinnaker but not up and down, as the bars
were only 1/8 x 1/2 aluminum, so they only helped pull force, and side to side force (because they formed a truss) but no compression force.
Keep in mind It's basically a rubber like boat 20 ft long with a triangle sticking 18-19 ft in the air which is held rigid at the mast holder and a completely flexible mast, as the boat rolls through the water and waves it all bends and flexes all over the place, the top of the carbon mast flexes forward, back, and side to side 3-4 feet easily.
Now here is a video with a sq tubing bow brace sailing in light conditions (winds were 5-6 mph and the sea was pretty flat). Watch the bow of the boat, it doesn't flex or waver at all. Think of the bottom of the hull as rigid, then the braces as rigid with about 1 1/2 ft in between, think of the front section of the boat as a cardboard box with the hull bottom as the bottom of the box, the braces as the top of the box, and the side walls of the hull as the sides of the box. Now glue the box to a wall by one end (with the wall you are gluing to simulating the super strong mast area of the boat). Now go to the end of the box and push it up and down, you will see the sides trying to buckle a little as you add more force but the top of the box remains fairly straight. Now take that same box and cut a giant hole in the center of the top almost to the edges in the center (that's your hatch opening). The front of the box (simulating your bow) will wave up and down and back and forth like a flag. Now lay a rigid piece of plywood on top of the box loosely. When it's sitting still the plywood remains sealed against the top of the box (exactly the same as the hatch cover does). Now pull up and down and sideways on the front of the box (simulating wave action). You will see massive gaps forming in the opening continually as it moves around, this is where the water rushes like a flood into the hull. The actual seal type name eludes me right now, but think of a canning jar and a rigid lid, both the canning jar and the lid must remain rigid for the seal to work. Now think of the boat as a Tupperware container (flexible), and try to seal a rigid metal lid on top (doesn't happen), that simulates the hatch seal system that Hobie uses. Now go back to your cardboard box still hanging on the wall in your living room for no apparent reason, and your wife is about to leave you over this ( LOL). Now make a foam plug about an inch or two thick that fits perfectly into the opening of the box. This is what they call a cork in a bottle type seal (the same type seal used in the 8 inch twist and stow hatches). Now wiggle the end of the box up, down and sideways. You will see that the seal is much more solid, and the flex on the box is similar to when there was no hole at all.
Sorry it took so long to get there with the explanation, and soooo much detail, but I can't explain it any other way.
We were averaging around 8-9 mph, and I think top speed for the day was around 11mph. I always measure the amount of water I take into the hull, we were out around 3 hrs that day and I took in about 2-3 cups of water into the hull (I have no idea where it comes in (probably a little from everywhere)), and we used about a dollars worth of gas (powersailing).
Even with all my hardening my TI takes on a lot of water in rougher conditions. Her and I went 3-4 miles offshore a couple days later in 12-15 mph winds and 3 ft rough chop offshore where I opened the boat up and pushed it pretty hard (which I normally don't do since it is mostly rigged for the very light conditions we normally have in this area), at times we were hitting 15-20 mph. Even with all the hardening I took in about 3 gallons of water into the hull in about an hour (even with all my junk the boat is still not suitable for offshore in anything over 15 mph winds and 3 ft chop). Of course I carry a nice pump on board (LOL), and all the required safety stuff, a Boat US membership, and triple redundant everything .
Seriously if you want a boat you can push hard offshore, I would be looking for something else (just my opinion).