If your talking about the LS6 intake and not the SLP w/egr than you can find one cheaper. I bought the SLP LS6 intake from speed engineering for $439 on sale. Your stock p/p TB will work great with the intake. As far as gains, I don't know I havent even had a chance to drive it yet. Tomorrow I'll give it a run on the old buttdyno. As far as tips I pretty much followed the instruction on
www.ls1howto.com. They are better than the ones SLP sent me. I took a nail and bent the end to pop the clips off the fuel injectors. Neither set of instructions says how to take the injector harness clips off. The ones under the cowl were kind of hard to get to. You will need to use rubber bands to hold up the last 3 intake bolts on the drivers side and the last 2 on the passengers side, as they can't be taken out with the intake under the cowl. Once you get the intake bolts out, disconnect the hose that joins with rear drivers side of the intake from it's other end at the firewall. You can then turn the intake counterclockwise and pull it out a couple inches. As you do this, use your right arm to reach around the back of the intake and hold up the hose that you disconnected and lift it carefully over the oil sending unit. You will be able to feel it sticking up between the intake and the hose. Once you've got it out a few inches, you can disconnect the sensor and small hose on the back passenger side of the intake. Then you can pop off the injectors by pulling up on the fuel rail and base of the injectors. After that you're home free. Putting the new intake on is the easy part, just remember to take off the knock sensor clips and tape. You can also use some soapy water on the heads to help the intake slide on. Oh yeah, put a little bit of motor oil on your injector o-rings before you put them back on. Good luck.