From what I understand is that NorCal DC4 is right in that they're strong racing transmissions without synchromesh, but the gears are dog-eared, meaning that you don't have to clutch when you upshift, you just need to let go of the gas. You still need to clutch on the downshifts. Ultra-precise rev-matching is not necessary to change gears, but as always it would be much more beneficial.