[s-cars] Turbo rebuild

[David Giannandrea]

Thanks Joe for the insight. 

To "only increase boost threshold" was what the rebuilder and I were hoping
for. The stock urS4 is gasping at the upper end. I typically enjoy the
torque, shift early. 

My concern is turbo lag. I don't want to loose that wonderful torque that
starts at ~2200-2500 rpm.

Note to Calvin: a malfunctioning pressure release valve (the one that
controls the turbo bypass valve?) could either: 
	1) cause bypass (=power loss), 
	2) inhibit bypass (=pressure/power spikes, engine danger).