Difference between 2.0 and 2.1?
 

anyone know the differences in the RTEK 2.1 and 2.0? tried looking for 3 hours to no avail:( also if i have the throttlebody mod done to my car should i buy 720cc secondaries? car currently has 550's all around, no emissions, no omp, stock fuel pump and rails, vmount and stock s5 turbo.

now is that for the s4 ECU only? i noticed on that page it didnt say anything on s5s

There is no 2.1 for the s5.

perfect thats what i was curious about! thanks man, hope life is going well since the site closed:)