Likely as not any options have zero residual value. It might ease the resale but you aren't going to get back your thousands you spent on them from new vs buying a poverty spec car.
Particulary not with something like a GTI because UK base spec is very high
Go on then, I'll bite. You've trotted this out several times recently, and it makes no sense whatsoever. No option will retain 100% of it's value, we can all agree on that, but when I've been looking for used examples, or if you ask the people who've been in contact with me about my car that's going to be for sale, there is a consistent answer... they've wanted certain options on the car and they are happy to pay more for it. More often than not it's been one or more from 19's, Pan Roof, Paint Colour, Dynaudio or DCC. With that in mind I can charge more for the car than a base spec car. If there's less cars out there with the options, supply & demand will dictate I can charge more.
CAP trade gives a base value for dealers to work from, and it's in their interest to try and get CAP, that doesn't mean they don't value cars with options higher, of course they do because it's more desirable and more margin by pricing higher, they just want to retain/gain margin where they can so will bid lower.
When my order with VW was cancelled in the summer of 2018 due to WLTP, I spent months trawling used websites looking for a car that suited. Cars with no options sat around for weeks on end, not moving, but if something came up with some of the grail options such as DCC or Pan Roof, OR Dynaudio, they would be snapped up within hours. That's fact, not me making things up. I would miss cars by a matter of minutes. As it turned out I was lucky enough to get my original order, but there were plenty of people at the time looking for cars with specific spec, and they were significantly more expensive cars than cooking spec base cars.
Am I stupid enough to think the £595 I spent on the electric memory seats will be retained, of course I'm not, but decent options retain on average 20-30% of their value, so in my Golf's case I can easily charge c£2k more than a cooking spec equivalent.
I read this quite a lot on here that UK base spec is "high", it's not, else options wouldn't exist. The simple fact of the matter is you got adaptive cruise control as standard, but apart from that there's very little over other brands or similar price points that is above and beyond, maybe heated seats.
The bottom line is a Golf is a swiss army knife, used by many people for many different reasons. I specced mine high because I wanted comfort and luxury, so I accept some options won't retain as much as others, but there is a no denying 19's, pan roof, dynaudio are three options that buyers look for when buying, how many threads appear on here talking about it! On the flip side there are people who are happy with base spec and there's nothing wrong with that, but your remarks about options adding nothing to future values is quite frankly rubbish.
And before you ask why a GFV doesn't move if options are added. VAG tried that once in 2015-2017 with the Q7 and MK3 TT, options were considered in GFV's (you could spec 21's on a Q7 and it wouldn't change the cpm because the GFV was higher) and they got burnt. They lost more than they could/did with a flat GFV, so it was scrapped.