i'm talking about near perfect / new parts. especially if you want a concours car (i don't), but i want most things to be very accurate. to me, good condition isn't good enough in most cases. trust me, i have bought a lot of used parts trying to find excellent parts. taillights for instance, i owned 7 or 8 sets at one time ... i got 3 really good right tails and 2 really good lefts ... and according to the initial pics they all looked like they were going to be very good. rear bumper - find a very good rear center trim. finding rear underriders takes a while too. for a while you couldn't get the rubber pieces on the underriders. only pieces you can readily buy for the rear bumper are the rubber pieces. front grilles - you can buy half decent grilles, but you will have a lot of work to make them look good enough to put on a newly painted car.
i didn't say anything about dash wood - completely aware of the options as Gary + I redid mine. its been NLA for a long time.
yes, there have been some ill-fitting BMW parts, and we are likely going to continue with that problem. they have fixed some of those. for instance the current rear belt trim fits. the ones from 4 years ago didn't have a prayer. not all aftermarket parts are worth buying - i will remind you of the w+n belt line trim 'T' bolts.
w+n have done a lot for sheet metal that you can't buy from BMW. its hard enough to get the correct brake calipers
my point is that as values continue to rise, you need correct parts to complete a car that is at the upper range. look at 911 values and the ability to get great parts for old models (expensive, but correct). i think that is your best chance to have a car worth more than the value of the sum of the parts.