Hello so i've been searching the forums and am not completely understanding some of the threads I have found about this so here goes. I have an s5 shell with what appears to be everything but the ecu harness and ecu I just picked up a s4 trans and s4 ecu harness from a convertible (guy threw in the ecu for free so i wasnt complaining) along with some other s4 parts. My question is if I drop a s4 motor into the car with the vert harness even though mine is coupe would it work? As long as I get a vert ecu? And would it be less hastle to get an s5 motor and ecu and harness and just use the S4 trans?

 

You can use the S4 trans but you need the cross member for that trans to install it to the chassis.
To make things real simple I would personally get an S5 engine and it's components to install into the engine bay.

 

Thank you i got the cross member with the trans and I'm just working on the s5 motor ecu and harness now