What's the Hardest Car to Work On?

I still have scars on my right knuckles when I spent the better part of an afternoon trying to replace a single spark plug in a WRX. But that's nothing compared to what it takes to replace an alternator on a V10-powered Volkswagen Touareg.

Redditor SoWhatComesNext jumped into this thread to show what's involved with a seemingly simple bit of maintenance on V-Dub's V10 TDI. But it's emblematic of a larger issue when it comes to working on modern cars.

With automakers using every available fraction of a millimeter under the hood, tight packaging and specialized tools have sent more shade tree mechanics into fits of rage than Lucas electronics or untunable carbs. So what's the worst possible car to work on?