$3000 I would first start off with a cam,(look into VHP) you will need springs and few other things to ge tthe swap done, since your paying for someone to do it cost would be about $350 for the cam and $170 for the springs and about 300-350 to install. also do a converter, I have ben checking out the trail blazer converter which cost about $200 which is suppose to stll up to around 2600rpms and is alot cheaper then the vigilante and yank. But if you plan on alot more horsepwoer go with a vigilante 3200. I would always tell you to put a shift kit in with the stall and have either a custom tune or mail order tune done. Where are you located so I might be able to give you some shops that dyno and and tune and install all this. also you could keep this stock and throw an sts turbo on for a couple hundred more dollars and your will see huge gains and drivability. that pretty much my goal and process your jsut beating me to it.

 

I agree, I would call VHP and talk to the people there, they will help you with the type of cam to pick out. Also to the tune, and long tubes, I would go ASM or dynatech. I would suggest a 2600-3000 stall and shift kit to help the trans, it got a 4L65 right? Rid all of the torque management and that should get you in the 13's. Pulleys help but I think they are a waste of money, believe me I got them on my truck.

1000-1200 for cam kit including JWIS timing chain and LS6 oil pump
895-1300 for ASM to dynatech headers.
450 for a tune.
450 for a TCI stall, 200 for shift kit, and 150 for servos

 

For $3000 go and find supercharger and a good tune, you'll really like the kick you get from that.

Future improvments would be:
-cam/heads <$3000
-headers w/free flow cats <$1000
-3000 Stall and shift kit <$1000

 

I dont know why so many are wanting "to get as much HP as I can without going to FI". FI is the best bang for the buck for the most part and it can be done in a weekend. The potential for more power is also much greater. That being said, I think the STS and Radix are the best deal out right now. Thats what I would do if I had it to do over. Try to ride in and drive some trucks with combo's that you are interested in before you drop a bunch of cash on a whim.