For a supercharged car I'd run 10:1 compression pistons. Stock sleeves are fine. The LHT intercooler is a great item, we had alot of success with it a couple years ago on a supercharged gsr motor. Another thing to consider if you don't want to spring for the intercooler setup right now is to keep the small 6psi pulley and run a wet shot nitrous. This does two things. One it cools the intake charge a good bit leading to more power and it makes power just like nitrous should. I've seen a gain of 60+ whp on a 35 shot on jrsc cars due to the cooler intake temps.

I believe the ls jrsc kit runs the m44 blower I believe and they do not like running much more than 6 psi. They will heat the air way too much if you try running 9psi or so. If you want to do that the lht cooler is a MUST.