Sorry, I wrote a reply to your PM and forgot to press send
Unfortunately you're going to have to figure the clutch out from scratch. There's almost nothing published on how to do it because its very difficult and there are only a few in existence. I didn't take any pics of mine and you can't see it when its installed, but I wouldn't recommend trying to replicate anyway it because it still doesn't work like factory even after hundreds of hours invested in it. There's so little room to get everything in there, everything is a compromise. If you have big feet, pedal spacing also becomes a problem because of the bulge in the tunnel. I had plans to perfect mine and make a bunch of them to resell, but in the end its not good enough to sell to people for the 4-figure price tag it would require to be worth it.
While I love mine dearly and its the best mod I ever did to it, it has been an ordeal to get there and still isn't perfect (or repeatable) after thousands invested and 3+ years refining it. People who think its cheaper than rebuilding the auto are unfortunately in for an very unpleasant surprise.
Your ENV is from a B6 Audi A4 2.5TDI, which is a little too high geared for an S8. 1-5 will be close to the original auto gearing, but 6th will be like mega overdrive and will do 1800-2000rpm at motorway speeds. Great for fuel consumption, not so much for accelerating
You'll need to change down to 5th or even 4th to swiftly get past things, unless you cruise at like 120+ in which case its fine
You've probably already noticed it has the small 88mm output flanges, but I think Mario has 130mm flanges to match the D2 front shafts so those are easy enough to swap over.
Watch out when bolting D2 gearbox mounts to the side of the ENV. Later versions of the 01E had different spacing on the bosses in the castings so need spacing out with washers so the D2 mount bolts up. They also didn't always use all the mounting holes so you may need to tap some of them out to M10.
One other thing to note with this gearbox is that the D2 original shifter that Mario has won't fit it as the casing is slightly different and the lever which goes side-to-side doesn't clear. You'll need to extend either the B6 A4 shifter that goes with the gearbox, or use a C5 A6 shifter which is almost the same. They mount differently to the original D2 shifter but its easy enough to make a frame to bolt them to the D2 tunnel. I'll see if I can find a pic of one of those as they were used in the D2 5 speed manual so a factory piece exists for that, albeit unobtanium so you'll need to copy it.
See if Mario can find you original gearbox cooler lines. They will bolt up to this and the D2 rad for a nice easy solution. The ENV has the larger sump and greater oil capacity for better cooling, same as the original S8 version, which is nice.
Oh, and it has a 3.889 final drive (35/9) so you need to change the rear diff in an S8 to either the B6 ETS code that came with the ENV gearbox, or DUP / EUT from an A8 3.7, but those at least are bolt-in.
Pull the lower dash and spend some time lying in the footwell looking up at the mess in there. If you still want to try it, pull the rest of the dash and work out a solution. Good luck!
