It's a combination of tranny gears, rear gears and tire diameter. Yes I think you would be hard on your clutch starting with 3.08 gears and an M21.

Your M21 with your 3.08 gears would be the same as an M20 with 2.68 rear if the tire diameter is constant. But that's just the first gear, In fourth they are both direct and the engine rpm will be the same with the same gear. You don't want to be any higher than a 3.55 if you're going to drive on the highway. I would suggest a compromise between first gear launch and highway driving of something around a 3.36 rear. If you really can't live with the launch using a 3.36 maybe you can change the gears in your tranny, I don't know.
Before I rebuilt my engine and replaced the gearbox I started from red lights in second all the time, hardly used first gear with the 3.73 rear.