Get a boost controller and you can up the boost level assuming you have the tuning and intercooler to complement the higher amount of boost. I believe you can retain AC with Revhard and Drag kits as well. Out of the box, the Greddy turbo will outperform the JRSC on the B18B. If you look on JR's website, they only got 160 whp out of a JRSC B18B....pretty pathetic if you ask me.