TMU help. What is the impact on value for a collector's car?

Hey all, I'm looking at buying a 1988 M5 for personal use that was TMU the last 5 years. Mileage was otherwise well documented by a BMW dealer earlier in life.Can anyone share their experiences on the value impact of having TMU on a car like this?What will I be looking at down the line as the value goes up, and what is my negotiation power in terms of buying it right now? via /r/cars http://ift.tt/2tGcrFd