Given it needs work, and has some gaps in the history and is not the "ideal" interior, black will all ways be more popular with buyers.
I would keep looking or get the priced dropped significantly, to reflect the work and your concerns.
Turbo prices have a really wide spread, recently from £80k - £150k.
Turbo buyers are fussy and rightly so, a good turbo is a delight to own and drive, many are now money pits, that have low miles but still require significant spend to get them up to a high standard.
The Black TT at Hofmann's and the Arena TT at Avantgarde are both cars I have previously owned in years gone by.
Turbo's never seem to stick with owners for long, they seem to be bought driven for a short period and then resold, relatively quickly.
Enjoy the chase its all part of the fun.
Happy Hunting.