Froggy:
It all depends if you want to push or pull!
RWD cars push, FWD cars pull.
RWD cars are quite useless in snow and ice.
FWD & 4WD the only way to go IMhumbleO.
With FWD, the is no massive transmission tunnel to obstruct the comfort of the middle rear seat passanger.
With the advent of all electric steering systems the purpose of RWD for unadultrated steering response is no longer valid as these steering systems are more or less devoid of feel.
RWD is great for supercars due to their prodigious power requirements and a lot of pushing is needed. For a Golf it would be pointless.
For the real world FWD is best.
Now a rear/mid engine RWD car should should be ideal. But then there are other aspects that cause impracticality.
There was an article along these lines in Autocar some months ago.
And that, my dear Froggy, is MO and I am unanimous with that!

After all this irrelevance and diatribe, my answer to your question on cost: I don't know!

BTW: Are you ordering any bits and pieces from Gulfstream? I will be, as he seems very helpful and his products are good. Also, saw German e-Bay regarding Xenons. Quite expensive once all the bits have been bought plus the installation costs.