With the new grip from the added drag tire compound, is it best to run 3 or 4 gears on the quarter for most cars now?
Really depends on how long of a first gear you can get away with. If you can tune the first gear to be as close to wheelspin as possible, adjust second so that it picks up where the torque peaks and so forth. Then you just choose wether you want to strech gears a bit for a 3 gear run, of you want to shorten (or shortshift) them a bit in order to get a 4 gear run.
Well that is my way anyway
4 gears on most cars, unless it has a lot of torque and needs a long first gear. Look out for weight too, usually anything over 2,700lbs need 4 gears (usually). Some cars even run better with an incomplete 4th gear (if it’s pretty good as a 3 gear but not good enough) then maybe try that.