lots and lots of questions

Im new here and i ran a search for most of this stuff but theres too much. I have a 1990 Bronco w/ a 351w. I need to know a whole bunch of stuff. I want it lifted between 7-9" total but i dont want to blow a whole bunch of money on things i dont want to (like longer drive shafts and such). So here we go (any help would be cool):

1)Whats the biggest tires i can fit w/ a 3" body lift?
2)Whats the biggest tires i can fit w/ a 3" body and a 4-6" susp lift?
3)If i get a susp lift will i have to lengthen my drive shaft?
4)My check engine light comes on when its raining or snowing. why?
5)What is the stock transmission?
6)How big are the stock axles?
7)what is the stock transfer case?
8 )How much is a decent locker?
9)what am i getting for gas milage right now?
10)what could i do to make the shitty gas milage better?
11)what is a good sight that sells mostly bronco parts and things?

any answers would be awesome. thanks.

-Nick

edit: 1 more question: whats the gear ratio on the stock tranny?

call the drive train ware house they can answer most of your questions (1.800-269-5889 ). Autozone can pull your check engine light code for free. galons used / by miles driven = mpg ( eg. 15 galons / 300miles = 20 mpg )fill your tank reset your trip odomiter or write your mileage down. when you fill up again figure out miles driven and divide it out. Any thing over a 3-4" lift and you will need drive shaft modification also longer brake lines, steering links spring wedges etc.. $ goes way up when you over 4-6 inches. 3 " body lift may need lengthened steering shaft e brake cable master cyl lines etc.

You could probably fit 33's with a 3" body. Add a six inch suspension and you could probably fit 38's. Your gas mileage will go nowhere but down when you add larger tires. Your stock tranny is the A4OD. T-Case is BW1356. Axles are, Front44 TTB (Twin Traction Beam) Rear: 8.8". A good locker will cost you $500 or more plus installation. There you go. By the way you will have to lengthen your driveshafts with a 6" susp kit. Not right away but eventually. Also you are going to want to swap out the gears when you put on larger tires. Add $350 for a R&P set.