its illegal to even do an usdm ls swap thats newer than your car??damn thats ghey
as for who do to it, do it yourself
but if youre looking do build your motor na, you should get stronger rods, higher comp. pistons(heard good stuff about endyn/wiseco pistons)upgrade your valvetrain and get a more agressive cam/camgear tu tune it. I never really took the time to learn building up NA engines too much, cause im set on FI. I think all that crap is good to start with tho