1) When people ask you, why you bought an old geezer bike? just say, "You've never riden one have you?" then laugh at them like they are the idiots. Which they are.
2) Other people have addressed your air filter and download question....and I agree
3) Between the left saddlebag and fender is an air valve for the rear shocks. Buy an HD air pump. You will probaly need 12 to 15 lbs (solo riding) on an '08 model. Pump the air past what you want at least 3 lbs, then realse the air down to what you want. This will keep the oil from the shocks out of the air line.
http://www.harley-davidson.com/gma/g...bmLocale=en_US
part number: 54630-03A ...........................MSRP: $46.95
4) I have a 21" front rim with an Avon Cobra tire and never had to rasie the fender. It you do, all you need to do is drill out the rear bolt hole, then tilt the fender up in the rear. That will stop the rubbing from the tire with heat expansion.
5) Buy all the parts you can bolt on yourself over the internet. You will save at least 20% usually. I use Zanotti HD out of Butler, PA
https://www.zanottimotor.com/