The biggest thing I learned after being an avid BMW fan and owner of BMW's pretty much continuously over the years since I was 16 years old is; modify to taste, but keep all of your original parts. It's really that simple. Keep a lookout all the time for hard to find original bits, whether NOS, good shape, great shape, fixable, buy them if the price is right, store (hoard) until the day comes that you need it. That way, if you ever sell it, you add a lot of value to the car if you have a numbers matching motor, original 4-spd. if converted to 5, correct date matched steelies, bus steering wheel, whatever. Even the little pieces, you never know when you may need to reference something or need a part for them like the clock or other gauges, or help a fellow member out on here like a lot of you do with parts they may need. Grab them when you can so they can be re-used to save these wonderful cars. Get rid of the real junk in your garage and save space for what is important, NOS replacement parts for your ride!!!!!
Get rid of the couch and TV in there, put in a workbench and storage racks and park your BMW back in the garage where it belongs! Carry on.......