since the 3rd gen is a twin turbo, do u have 2 blowoff vavles??and whats the difference between between wastegate and blowoff vavle

 

waste gate closes under engine load, allowing exhaust to go through the turbo charger to spool it up instead of around it.

If I remember correctly, a blow off valve is like a pressure relief valve. It relieves boost pressure to prevent damage to the intake plumbing. Some are adjustable and can prevent more air from being forced in than what the fuel system can handle. To find out what PSI starts causing you to run lean, you need to dyno the car and have the air fuel mixture checked out with a wideband O2 sensor.

 

but do u need only one blow off vavle or 2, since u have 2 turbos

 

You should only need one. A twin turbo is 1 turbo charger with two compressors. They share the same turbine wheel and are one complete unit. The smaller compressor allows boost to be applied quicker, and the larger turbo allows boost to be applied at higher RPMs. (in a nut shell)