If you could do the cam yourself you would save quite a lot. It's not that tough. A convertor will cost you more than the $500 limit. A shift kit install with servos will eat up your funds in a hurry. How about a transmission cooler to save you money down the road? You could add a nitrous kit for just under $500 if you do the install. Go conservative with a 50-75 shot. DynotuneNitrous.com has really reasonable prices on their kits.