my an600 is finally road worthy... a few questions

[dawn_and_darrian]

After dealing with the DMV and jumping through a few hoops today I am finally ready to register my vehicle.  Apparently few people know that 2 cylinder engines smaller than 650cc are exempt from emissions.  I still had to take it to a testing station though to prove that I had the correct engine in it.
Anyway, on to the questions:
1) The noise.  I'm actually a little embarrassed when I drive this car.  It's SO LOUD.  Given that half of the problem is that my exhaust hanger is missing so the exhaust pipe will rattle against the rear of the vehicle.  This will be fixed soon.  The car is just so loud though... much louder than I expected.  I imagine there isn't much I can do about that, is there?
2)  heat.  The engine bay gets hot REALLY fast.  This is my first air cooled engine.  I didn't expect it to get THAT hot.  WOW!  Is the only viable solution the oil cooler?
3)  Gas mileage.  I think I saw the gas gauge drop from around full to 3/4 after driving 20 miles.  I know that these tanks are small, but there is really no need for it to get such poor mileage.  Could this be caused by the carb being improperly set up?  I have a newer style carb that the previous owner obtained from Mike O'Conner.  I also have an after market electronic fuel pump installed.  I'm unsure if this could be part of the problem or not.
4)  Exhaust.  I think there is another post about this, but I'm thinking of redoing the entire exhaust.  Right now it rattles, shakes, and leaks fumes.  It's rusty and not to pretty.  I imagine a new exhaust with a new muffler could in fact also help with the noise.  Can anyone recommend a muffler shop that can do this?  I guess I could start calling around local shops myself.  Are there alternatives to these mufflers that are cheaper than Mike O'Connor's $300 chrome muffler?
5)  Clutch.  Either the pressure plate is too old or the clutch cable needs adjusting.  I'm hoping it's the later.  I need to push the clutch all of the way to the ground and I still get a little gear grinding when I put the car into first gear and switch between gears.  Could this be something I'm doing wrong? I'm the first to admit I don't know a thing about the syncros vs. non-syncros.
I had a very full day today with this car.  i drove it to the honda dealership and asked for a few parts.  I then asked the lady working the parts counter if anyone inthe back was interested in seeing a 71 n600.  She said, "no, they're all into the 99 Civic SI's."  Maybe I'll go back when she isn't working.  I think this car is great and i'm certain that some of the honda enthusiasts would love to take a look at it.
Anyway, if any of you can answer ANY of my questions please let me know.