well,
As the guy who did the Audi (VW) swap into my 40, the actual mechanical interface is really the least of your worries. The adapter plates took me a while to do (did em myself) and once that's all out of the way the wiring isn' so bad either.
I haven't had the time to finish up the little stuff: no EVAP, no VSV, no EGR, etc. That's all coming up soon.
On my setup, the MFA system uses it's own sensors which are now hanging limp, and the actual ECM uses companion sensors, then it's the ECM that outputs info to the MFA, dummy lites, and other body modules. I have a VAG-COM setup (RossTech) purchased off ebay for $25, and I bought the license for $75.
I used Mitchell on Demand software for wiring diagrams and a russian website that publishes complete FSMs on line.
here in BC, there's lots of guys doing 1.9 / 1.8 TDI swaps into Samis.
perhaps dahlback racing has some upgrade kits if the V10 isn't muscle enough for you. (home of the 900 BHP 2.5 litre Audi powered golf)
http://www.audituning.com/
Max. power (V10 TDI)
355 hp (262 kW)
Max. torque
629 lb-ft
Changes
New E-prom.
Price incl. installation
2297 EUR excl. VAT
Note
This upgrade is TÜV-approved and meets the current european emission regulations. The software maintains full functionality in terms of diagnostics, engine protection and fault code memory.
HTH's