Ok, question. Would it be OK to drive a 95 L67 car with a noisy SC?

The distance would be about 60-70 miles. Do you think that would be an issue?

I would just try to trailer it, but the trailer is occupied by a Grand Prix that is noisy at the other end.

noisy as in coupler , or other noise?

No clue. Haven't heard it myself. I would like to assume it'* just the coupler, but there is a chance it isn't.

Would it make a difference? And what else could be making the noise?

running on a loose couple shouldn't be a problem for a little while. if it'* a screetchy or squeeling noise, it could be a bearing, I would guess more likely an idler pulley in the belt path somewhere. then no, if something on the belt path freezes up, you have problems out in the middle of nowhere

Check your water pump pulley, Thats were I almost got scammed from the dealer saying it was the supercharger gone bad, Check the water pump, I wish I did that first

Harmonic balancer (crank pulley) is another common one on 3800s. I can't count how many of these I've replaced. They make all sorts of noises when the rubber starts to seperate. For some reason on the supercharged engine, a lot of mechanics just assume it'* the supercharger. If you can take your belt off (all you need is a ratched and a socket, 15mm or 18mm or something, I can't remember) and wiggle the pulleys, you should be able to isolate the noise. If there is "slop" in the supercharger pulley (it turns back and forth a ways before you can feel it engaging the rotors and turning them) then you need a coupler.