Replacement Brake Rotors

[ninjabones]

I agree with Bob with regard to leaving the backing plates in place, especially if you drive the car on the street and/or in the rain on the track.  Some people remove the plates for percieved increase in air-flow and subsequent cooling.  If you don't have an overheating problem, I would leave them in place (even if you have an overheating issue, I would probably address via a different mechanism first). 

The real question is, do you have an overheating problem and how were you able to diagnose it (are you cooking the fluid, are you feeling pad fade, under what circumstances, have you measured rotor temps with a pyrometer, are you overbraking, etc)?  Each of these issues can be addressed without necessarily removing the backing plates, such as: titanium shims behind pads (shield calipers from heat transfer, at the expense of higher retained temps in brake pads), running different fluid like SRF, changing friction material to a higher temp compound like RS14s, running ducts to the rotors, etc).

I run ATE blue/gold fluid, pagid RS14 or RS19 pads on stock 993 NB calipers, stock porsche cross-drilled rotors, 3" ducts to the front rotors and have left my backing plates in place.  I have yet to have any overheating issues.