Just to clear somthing up.

If you do it by the book & legally, you can't put an older engine into a newer car at all under ADR's & engineer's.

Eg., you can't fit a VN 5L into a VS 5L, you can't fit a HK engine into a HG etc.

You can't fit a 86 KR 16V into a 88 model.

But this is only if you do it by the book.

Why would you fit a VR6 into a Mk4 anyway.

It's already been stated that a lightly tuned 20VT will pump a VR6!

Also, if you planned on 4 motion gear, you will need a the entire Bora to cut the floor out to fit a AWD stuff. Waist of time.

If you want a VR6 in a mk4, buy a bora!