Dude... Not being rude, but have you done any research on the RBs in general? Read up on other forums or swap guidelines and such? Seriously, you are asking so many questions that with some time researching, it will solve all your problems.
And to your question, yes, you can put a 20 tranny to a 25 but the gear ratio isn't necessarily as good nor are the internals as strong or can take the amount of abuse/power the 25 dishes out as well.
Most things with RBs are dependent on what you're looking for or expecting. First figure out specifics of what you want then decide which engine after.
Topic: Rb20det/rb25det (Read 2090 times)