I will let you guys help me build this!!!
 

I have a 91 mustange gt. Bone stock! It is winter now and i have 2 credit cards lol. No i really have about 5,000 dollars to spend on this thing and i would rather go with the mods you guys tell me to so i don't waist a bunch of money on junk!! So if someone would be so kind as to tell me all the mods you would do to this car and maybe some links to some of the parts you talk about would be great! 1 other thing do you think it is possible to get a low 12 second car with the money i have? Thank you all!

Yes, very easily, but I have a few questions though.

How many miles are on the engine?
Does it smoke or leak fluids?
What transmission does it have?

About 110,000 miles does not smoke or leak fluids! But the last time i drove it i heated up the brakes pretty good and now i have none! Oh also it is the 5 speed! I also have a buddy here that does nothing but pro street chevy's. (What a fool!!) He wants to back half my car and put a set of ladder bars under it. Would that really help that much?

Nobody????

I guess my next question would be--> Do you want to run low 12s naturally aspirated or with a power adder (supercharger/nitrous/turbocharger)?

I would have to say on just straight motor!

Bone stock to 12's N/A with $5000? It'll be close, but I think it can be done.

Start with gears, exhaust and slicks or Drag radials. This alone with some good driving could have you in the mid to high 13's.
~$350 for gears & install. ~$600 for full exhaust (longtube headers, offroad h-pipe,catback). ~$350 for tires
There goes about $1300. Now theres $3700 to play with.

Subframes ~$120, Control arms ~$250, Drag shocks and struts ~$300, shifter~$180, underdrives~$100
$950 gone, $2750 left. you should be in the low 13's by now atleast mid 13's

Performer 5.0 intake ~$500, cam ~ $200, AFR 165's ~ $1250
gasket set ~ $150, 255lph fuel pump~ $120

This all would leave about $500 for whatever else I didn't think of.

To add to the list above:
Edelbrock Performer RPM intake (instead of reg. performer)
Ed curtis custom cam
bigger maf and either 24lb or 30lb injectors. Make sure the maf is calibrated for the proper injectors.

5000 would build a spiffy 347.

AFR 185 cc heads 1300 bucks
347 stroker kit (street) 1600 bucks
Edelbrock Performer RPM intake 500 bucks

machine work and ancillaries would take the rest (and maybe a bit more), but thats an easy 400+ hp on tap all the time.

Yah a 347 would be nice, but he said BONE stock, that means he's gotta do all the little stuff too before he can jump into a stroker motor. TB/MAF/fuel pump/ injectors/ suspension/ tires. Can't really support a 347 well without these beforehand