[COcyclist]

Cool swap! You are getting some really good FE numbers with it. I have been thinking a TDI swap into a Mk II or III would be a fun car to have. Less weight and frontal area than my Mk IV TDI. I used black foam pipe insulation stuffed between the bars for my grill block. It is pretty stealth on a black painted grill (see if you can spot it in my avatar). It is really quick and easy to add or remove depending on conditions. The diesel needs surprisingly little grill area because they run so cool. I have the upper blocked year round even climbing the passes and part of the lower blocked in all but the hottest weather. I priced the Snow Performance H2O/Meth injection kit and at $750 it would take a long time to break even on fuel savings. Might be worth it for more power on Pike's Peak but probably not for hypermiling.

If you have the OBDII port from the TDI a Scanguage is very useful. Instant and trip mpg, real time water and intake temps are nice to have. Can really help teach you when to EON (engine on) coast or to overrun (go downhill in gear-@ 9999mpg).

I deleted the passenger side mirror and folded the driver's side with a blind spot mirror glued to the glass. Also, I am sure you know you don't really need a muffler with the turbo and the cat. I substituted a straight pipe for it to make room for a flatter belly pan. I have a full belly pan from the front bumper to the back. No need to worry about exhaust heat anywhere except the cat/con. (see photos in my albums)

I am curious about tunes on a diesel for better mpg. UFO was trying to eliminate EGR for better mpg but it seems to have hurt his warmup times. If you have a tune that you think helps mpg I would be interested to hear your thoughts.