Performance wise I really like it so far. It has really good power delivery. Doesn’t struggle to get up to speed and over hills. It responds really well to the right foot!
With that being said I still think a re-gear is in order. First gear is kind of a pain and I find myself dancing between 4th and 5th when cruising 60 mph. A good set of 4.56s could only make this thing even better.
I think your 700r4 with 5.13s would be a great pairing for a TDI without having to change much else. Your first gear ratio is a lot better! A 2.0 CJAA out of a newer Golf or Jetta is a great starting point. They’re a common rail diesel and super easy to squeeze more power out of. There’s also a ton of them laying around from the whole “diesel gate” ordeal. I had also seen that someone was working on developing an adapter kit for the VW/Audi 3.0 V6 TDI. Not sure how well it would fit, but this would be an option to explore as well.