I wouldn't worry about going with another motor. The KLZE is not a huge upgrade. You are already at 170bhp. I would just decide where you want to go first off (how fast/how much HP). People have slapped turbos on your current engine many times. Not to mention alot more adding shots of N2O and getting great results. I would start with some bolt ons and go from there.
Oh and check out probetalk.com and mx6.com (same drivetrain and the MX6)