Need a little help
 

well i just purchased a 89' TII with a mustang 302 V8 in it. I just have a few things i need help with..

1. With the TII rear end how much power can these handle?

2. The guy before me kept it in horrible shape ( i.e. Wrong fuses, Not the best maintenance and so on). What small things should i look to replace besides anything dealing with the engine and tranny?

3. Does any one know if i will have to get a custom front sway bar or is there one out there that can clear a V8 and still stay under the hood?

You would get better answers if you ask the guys at v8rx7forums in regards to your swap and specifics: http://www.v8rx7forum.com

The guys on the V-8 forum like the T2 tranny a lot.
They say it's good up to about 500HP, especially if you don't drag/hard launch the car.

Auto trans are easier on the diff than manuals.

Excluding the engine/tranny, maintenance on the car is pretty generic (and in your case, even the power package is pretty standard) .
Just approach it as you would any 20 year old vehicle- meaning, be very proactive, not reactive.
For instance, I would consider it standard to remove every exterior bulb, clean the socket and then grease it before putting in a new bulb.
Go through the brakes- again, I would replace everything...rotors, pads, lines, MC and rebuild the calipers.

This approach might seem a bit over the top but has two advantages- first, you know the subsystems are in good shape and second, you'll end up all over the car and might find other things you'd normally miss.
You have to figure that whoever did the swap was working on pretty much the whole car and as you noted, they didn't seem too thorough, so it's certainly to your advantage to go through as much as possible and check their work.

As for the swaybar, it all depends on how they mounted the engine.
Grannies, Hinsons or custom install kit?