exhaust cut outs C5
I did a lot of planniing and measuring when I installed my round QTP cutouts. I had a set of Y-pipes that were part of my FLP headers that ended up not working with the electric cutouts. The Y-pipes were meant to be capped/uncapped manually so they fit in the larger, forward section of the torque-tube tunnel. It was a no-go with the QTP's though - not nearly enough room to do the Y-pipes with QTP's. So, I ended up installing them just before the over-axle pipe flanges and that worked out nicely.
A non-starter - Y-pipe trial fit

I modeled them up in CAD first to try different positions and then had an exhaust shop weld the flanges in.





Actuator switch

Custom ashtray replacement I designed and had machined from Delrin

There was a forum member (and vendor, IIRC) who welded a set into his Z06 Ti catback.











