So... I went and bought a 1996 Passat TDi for $400. It needs a considerable amount of work, but runs and drives... and even stops, sometimes.
So far I seem to be averaging about 36-38MPG, which is dismal for a TDi, but still acceptable for now [considering how cold it's been lately].
Some of the first things I plan on doing are cleaning and updating existing [OEM original] parts, such as vacuum/boost reference hoses, fixing the broken oil dipstick funnel tube, and eventually removing and cleaning the intake/EGR and turbocharger, all of which has never been done in 301,500 miles.
Currently, there is a MIL code for PCM rom check failure, typically attributed to the 4'' piece of vacuum line inside the ECM that runs through a bulkhead connector to the internal MAP sensor. This particular line, as well as the 34 feet of other reference lines, I plan on updating with silicone line [in OE color patterns] from McMaster Carr. The total cost of this about $52 plus shipping.
Further mods include upgrading to VR6 suspension/brakes, booster delete, belly pan, grille block, 1.5kw inline circulatory coolant heater, thermos bottle mod [Prius], CCV catch can, and lots of cleaning up and relocating parts of the engine bay, such as the coolant and washer reservoirs.
In addition to the VR6 [Plus] suspension swap, I'll be adding stronger struts and coilovers, but they're designed for an MK3 chassis, so at full pre-load they'll still lower the car about 2'', which should be more than sufficient.
Since the car didn't come with a grille, and I absolutely hate the front end of the car as it is anyway, I plan on skirting the bumper and closing off the grille/headlight area completely.
Pics to come when I get the gumption to battle the sub-arctic temperatures and get some. :P