Switched from Scumacher try-Ys to Pro Parts step headers.

That's good comparison, now I'd like to see one for the TTI's vs Pro Parts.

I might be doing that but in my case the proparts were so badly fitting it won't be a good comparison, as I had to smash in tubes to make them fit. Those tubes were too restrictive and the motor would not turn 6000. The torsion bars were in the way on the pass side. Now going to coil-overs so the TTI step for 440-1 / RB will fit. Maybe.