does anybody know anything about installing the apexi afc2 and rev speed meter ......does it make good gains, can it hurt my engine, anybody know how to install it???

 

you have to hack up your wiring harness to install it. not recommended diy unless you know what your doing. gains are all in the tuning. but expect 5-10 on stock and up to 15-20 on a car with boltons. its very similar to the reflash of the ecu.