My transmission is going bad and I was wondering (before I buy something that I can't use) if you can put an s4 t2 transmission in an s5, and, if so, what other modifications (wiring customization,etc. ) will be needed, if any.

 

yes but ratios are shorter on s4 bratha so id stick around with the s5 since its more drivable on street.... i know this because my s5 tranny went and im stock with a s4 lol