[jr_ss]

This is all readily available information at NICO. Do some searching.

I'm getting ready to do my swap and in taking some conversion steps early I found that when drilling the hole for the MC, a perfect size to use is 1 3/8th's hole saw. It's slightly larger (about 1/32nd larger) than the protrusion on the rear of the MC. This size will allow the rubber to be pinched inbetween the bulk head creating a "waterproof" seal, not that any water would get there but, it'll also help with the road/engine noise in the cabin. I would imagine that the S13 MC would be similar to/if not identical to the S14 and use the same size hole saw, but do not hold me to that as I do not have an S13...