S986..
Sorry to dive in here... good to hear that you have had a drive of the 130 Tdi.. As you mention, quattro handling is different but not really the dream you describe as standard (but dont be put off), its different. Ess3's ARB and suspension mods do transform things a lot. Read up on the info in the stickies, its invaluable.
Also as Glen says elsewhere, you cant bend the laws of physics and there is a good chance a 2wd will be slightly nippier and/or more economical. There are more friction losses in the quattro. Where is my dyno chart from Star.....
As standard 6th gear felt flat and it would struggle to pull, remapped again, its a different story and it does offset the friction losses. It wont go faster but it does accelerate harder.
I guess with the milage on these cars now it may be wise to check the suspension as mine went off at about 65k and was dreadful on the old standard stuff. I could guess that a diesel would be remapped, worth asking too if your buying.
Heres mine:
And yes, the Lexus lights are long gone. As are the wheels. Its on new RS4 reps plus spacers. Same height though. (dropped from "Sport" spec).
And this stayed on all the trip to the Alps, even 120+ on the Autobahn....till some Scrote nicked them in Cortina.
Currently averaging 38-42mpg. No new pics as it is in for fox collision damage repair...its due back tomorrow and I miss it..
HTH