Y-Pipe Specs (Stillen vs Stock)
 

So heres the run down on what I'm trying to figure out.

I got a deal on a stillen exhaust that I couldnt pass up, only catch was that it didnt have the Y-pipe section.

From what I understand the inlet flange of the midpipe is 3inches on the Stillen exhaust, but I cant find anywhere what the stock y pipe outlet flange is.

If they dont match up, what are some options for y-pipes that can connect the stock cats to a Stillen midpipe?