I was thinking of upgrading to the speed gallery y pipe kit. I was wondering how much bigger it was then the stock y pipe.

 

It is several pounds lighter and has a much larger internal diameter than stock. The opening to the TB is about 75mm and the two ends are about 60mm. I can give you exact measurements when I get home late tonight. You will need to use EVOMS IC hoses because the stock, SAMCO and AP hoses are too small in diameter. Alternatively you could use a 2" to 2.5" adapter with those hoses. In addition, the ends of the SG Y-pipe are much longer than stock and this means that the IC hoses must be cut shorter. There are good and bad points to this: the good is that the IC hose is shorter, therefore less expansion under high boost; the bad is that if you cut too much you wasted your hose and it also makes fitment difficult. I have an SG pipe that fit great on RobMD99's car but would not fit well on BlackBear's car. I intend to compare it to the spare stock setup and figure out what is going on but haven't had time. If you are interested in the Y-pipe and the two precut EVOMS silicone hoses, let me know.