Hey i have a '94 probe GT... I am thinking about swapping engines for the KL-ZE and also putting a T3/T4 turbo kit on....Is that a good idea? and what else would i have to do if i wanted to run around 10 psi of boost? Also what kind of exhaust system you think is the best for a turboed probe?

If you are going to boost it then keep the stock motor, it has lower compression and is more friendly to boost. Spend the extra money saved on a megasquirt fuel system and millenia S injectors. Safe boost limit on a KL series engine is really about 7psi without fuel system upgrades. I ran 7psi on just an FMU with no trouble. If you want to go for more than 9psi and drive it daily you should consider forged pistons as well.