2" seems to be wrong. I just finished doing a complete hardpipe fabrication and install on my friend's 87, I made the 2" ones fit, but in all reality, 2 1/4" would have been nice. So my final verdict is that from the first aluminum elbow after the outlet (haven't done from the turbo to there yet) to the intercooler to the 3000 pipe, it is 2.25". for future reference.
Anyway, pics will be up of the install later. It ran $130 in J-bends, 2' of 2" silicone, and a grip of t-bolt clamps, and about $.50 of electricity and wire for my welder. Not too bad I guess. It spools hella quick now too-around 2k RPM with a 3" suprasport elbow, RSR DP, 3" catless exhaust, and a profec b spec 2 at 12 psi w/japan style FCD.-as soon as the guy gets an AFC, I've got a lexus and 550's to install.