Thomas, on the 914's originally the black in the fender wells wasn't paint per se, but undercoating - either dealer applied or less frequently as a factory option. It was there as added chip & corrosion protection.
If yours is
anything but a concours queen &
you personally like the look of black wheel wells (
to hell with polls of other folks' opinions! ) - then definitely go with the black undercoating (Wurth Schutz & some truck bed liners have been recco'd on here).
If you're going to CW it, then I've heard 2 schools of thought on it, both with & without for CdE winners. IIRC the Sahara Beige owned by Steve G/smg on here lost out at the PCA Nat'l Parade - or at least was gigged points for it (rightly or wrongly by the judges) - because he'd removed the original dealer/factory black undercoating from the wheel wells, because Steve liked to show off the #99 customer special order paint color of the car.
Go to O&H Forum, "The few, the rare...." at it's nailed topics & see his 73 914-2.0, then PM or email Steve for his thoughts on it. If you're a PCA member, then you could probably also email or call the current nat'l. Concours Chair & ask the specific question & request a written reply to keep in your 914's file for when you show it & may need to challenge a less experienced/knowledgeable (on 914s) judge(s).
Of course if you're going the CW route, then you'll want to keep it the original color per the Karmann Plate (even if PCNA's COA is in error with a different color - they're often wrong), and resto it to as close to original fitment & listed options from the original window sticker &/or dealer BoS (or COA is those aren't available), with a few "personalization" additions which may not cost you too many points (e.g.: the period correct Porsche Crest shift knob, Porsche side stripes, SS HEs, etc.).
Keep in mind that originality is
not judged at all at the PCA's local chapter & zone & usually regional level CdE shows. I was surprised to learn when I took the Zone 8 CdE Judges School in March (to figure out how best to resto my 73 2L), that they're basically only judging who can be the most anal about cleaning every nook-n-cranny (drain vents at the door bottoms, down inside hood/trunk latches, etc. - I mean really? ......
REALLY!!?? ). I was expecting much more on who had properly restored & prepared their Porsches to each model's/MY's proper OE spec, than a "cleaning contest"!
Originality only comes in at the Nat'l./Parade level, and then usually as a tie breaker in tenths of points!
IMHO the lighter colored 914s - perhaps including black - look better with the black undercoated wheel wells, & I certainly prefer the added protection afforded by a good quality & properly applied full undercoating - esp. after spending a bunch of dough on paint/body work etc. on a resto. So I voted for them, but - as I said above - do what you like & want, & what fit's your planned use of the 914, & to hell with my & others' opinions, other than as informational input!
Here's a couple of shots of Steve's Sahara Biege with & without - or before/after his months of undercoating removal - FYI same car with & without for comparison!
Click to view attachmentClick to view attachmentHope this helps!