I think they are electric. The back of the gauge only has 2 wires, and no vacuum nipple. I think it's specific only to S15's too. You can use the holder in S14's though, but you have to cut the top bit of the plastic to fit.
bro..when my emanage put in, the error code of the rpm meter goes out....... cannot use the meter box... gt sot.... but the meterbox is fully ori and no damage done.. i hav waited for 3 month oledi....
my car engine...