hi i have a 2003 civic sir or si to all you in the states. i would like to put a rsx type s trany in it so i have a 6 speed. how hard is the swap? are there any hard mods to make ither under the hood or inside with the shifter?
please let me know.
shagy

 

Considering how relatively new both cars are, not too many people can afford to do that type of swap. You can probably find the info you are looking for here:
Civic Si - RSX Hybrid

 

you might need an ecu to cause goin from 5 speed to six speed