I don't have exhaust contact with either VerTT with the crossmember installed, but I am running SZ 3-2.5 in TPs. Are you sure that the exhaust hangers that attach to the back of the transmission are not upside down? (common error and affects the clearance)
Yes the TPS will affect your performance and may be part of the stalling problem as well. Set the TPS to .45 volts. I had the same issue this past weekend. Car idled great with a low TPS voltage but ran poorly. Make sure to reset the ECU per step 6 of this La-Z-Link