Bit the bullet last night and ordered a new inlet manifold for the RS4 - they're notorious for having inlet runner flap errors, which the ECU does not take lightly; it pulls timing, limits the revs and worst of all illuminates a warning light. You can drive around it to an extent by restarting the car and giving it a bootful but it got to the point where it was happening all the time, and although it might not seem a good use of cash (GBP 1k shipped) things need to work properly. So there it is.
Taking it for a service at Audi next week where they can replace this - hopefully that'll be the only extra works required. It's been great in the last 20k kms apart from the above, although a set of tyres will be on the cards soon - Pilot Super Sports FTW.
The Land Cruiser also needs a service (some 250k kms on it now, 80k when I bought it back in 2006) - it's got a leaky a/c pipe and needs a propshaft bearing but again that should be about it. Oil pressure is a tiny bit low but I'll replace the sender first before changing anything mechanical - been down that road before.