I've got pioneer's in the front at the moment with the rt3 and they sound ok but there magnet is still the same size as the ones i took out !! (slim fit)
but I have a set of infinity's to fit soon with custom door pods
The alpine head unit has more power than the rt3 and sound quite good with the pioneer's at the moment.
Proberly going to detach the stalk control from the steering harness and hard wire it to the alpine !!!! that way the VAN bus wont know theres a problem.