We could definitely get you a lot for 2500:)

Invest in tires before any hp/tq gains. The stock tires blow.

I say a good set of tires (even if you just upgrade the back tires) and suspension first. Depending on how much you spend on that, then I would go for a custom tune, off pipe or catted depending on the area you live in, an AB, and possibly a cai last if you have a little money left over. Also M6 or A6? If M6, scratch the cai and get a MGW shifter.
My top pics in order would be:
1. TIRES!
2. Suspension
3. Tune/off road x or h
4. Shifter
5. CAI
If you search classifieds for used parts on mutiple forums you should be able to do all those mods at once with $2500

M6 and thanks everyone for your opinions. Even if I can only choose one thing at a time I want to do things write and not the cheap route. I'll be sure to let everyone what I do and with pics

Don't know what line of work you're in but, you also may want to consider coupling your bonus with your tax return if that's the case.

-Alex

Buying the wife a new car with that... -_-

After taking a ride in Hddcrasher this weekend, definitely go with a good suspension setup. Tires, struts, shocks, springs etc. You won't even know this car has an LRA.

-Alex

Depends on what you are going for. You could get an Intake (~$300) / O-X/H (~$300), Axle back (~$400), and tune ($500-700) for that kind of money and make significant power gains.

If you are looking to improve the stance / looks of the vehicle you can do it via suspension depending on springs (~$250), shocks (~400-800, this depends on adjustable / non), panhard (~150). You could add other things to suspension mod which will help with traction / ride like UCA, LCAs, Relocation Brackets, Sway Bars, CC plates / Mounts. You could make a very large dent in the suspension and make serious improvments.

Wheels depends widely. $2500 would get you about what I have or you could go with many different options from like AM, Latemodel, who sell the cheap combos.

Appearance mods would vary greatly, kinda depends on what you are looking for.

I can't say I don't care about the looks but for my situation, performance is number 1. I want it to pull hard while I'm driving down the highway. I've spoken to Kooks and they're saying they'd give me a steep discount on their whole set-up when i'm ready to buy. That includes longtubes x pipe and catback.. I'm thinking if they keep to their word ill go with that and install myself and maybe ill have enough to get a CAI and tune... it seems like a long shot but ill see.

for 2500. i would get this.

SVE DRAG WHEELS AND TIRES $1300
http://www.latemodelrestoration.com/...-15X10-15X375-

SWAY BAR RELOCATION BRACKETS $40
http://www.latemodelrestoration.com/...-Mustang-05-14

OFF ROAD X PIPE $300
http://www.latemodelrestoration.com/...1-14-50L-XFM24

HAND HELD TUNER $380
http://www.latemodelrestoration.com/...-Free-Blow-By-

that leaves around 400-500 dollars for a tune. who you go with is up to you, but i recommend kevin dunn. or AED. this post obviously doesnt include taxes but lets say taxes werent an issue, i'd get that setup to fully maximize that hp you can get for cheap and have traction all day.

If you really want the car to actually pull hard, save that $2500 and save up more money for boost. The dollar per HP return for all the bolt ons for these cars just aren't worth it in my opinion.

I live closest to HPP and have used them. Didn't have a good outcome when they tuned my turbocharged 99 GT....

funny because coyotes make the most power on bolt ons more so than any mustang ever. weird.

They are also the most expensive parts ever for a mustang too. But then again i wouldnt expect you to understand anything when it comes to finances and returns on it.