I just got an 88 hatch with a 1st gen b16a. The mounts are "custom" according to the guy who sold it to me, so I am a bit suspicious of their quality. When I downshift from, say, 4th to 3rd, with the 3rd gear RPMs above 5k or so, there is a loud "clunk!" and the car is shaken for an instant. My question is, what's causing it? The clutch is ACT stage 2 (6-puck) with ACT pressure plate, and it seems fine. It's gotta be the mounts, right? Thanks for the replies.