UK Right hand drive Audi 200 Turbo Quattro problems....

["Paul Robinson" <paulrobinson.cameraman@virgin.net>]

Title: UK Right hand drive Audi 200 Turbo Quattro problems....

Hope someone out there in Audi land can help a poor Englishman with his aging 200 Quattro Turbo Avant (wagon!).....
My car is an '87 with a reasonable 227,000miles on the clock - never had the head off and still going quite strong but probably needing a little TLC before too long.  Using some oil, not really pulling the tree stumps as she used to, and just a few niggly little problems to contend with.
1. Lack of Power - a discernable difference from 30,000 miles ago.  Usually does 30 miles per gallon+ on motorway trips and about 20mpg in town.  The car idles with 0.6 bar of boost and reaches 1.4 sometimes 1.5bar. Should it idle with this pressure?  I have checked for induction leaks in all the normal places but nothing obvious.  I have a new set of injectors to fit maybe this will pay dividends?

2.  Rattly/tinkly noise from somewhere under the car - even with the engine off and coasting down a very quiet road this noise can be heard. Imagine a rivet loose in a piece of metal (heatshield?) rattling and amplified by the underside of the car.  could it be from the propshaft u/j or carrier bearing. Any ideas or similar annoyances?

3.  Turbo After Run Pump and Fan We don't often get very hot summer weather here in Britain but I drive in London Traffic - very bad all year and the car gets pretty hot. The Turbo Pump and Fan hardly ever operate - The Bentley book states that it should operate if the vehicle gets hot enough for the radiator fan to cut in during normal driving and the car is turned off with this fan still running. I changed the thermo switch which actually seemed to be faulty and the new one was worse - it operated the system with the car stone cold!  
Any checks one can do on this system please.  It is obviously there for a reason. Presumably to safeguard the Turbo.
4. Clutch and Gearbox  I fear the worst here - the clutch seems to get stiffer and graunchier all the time, particularly in traffic, and the gearchange is also very difficult once the car gets hot - 1st and reverse v.nasty!
Its been suggested that a change to synthetic oil in the gearbox might help some and the clutch is close to death.  Thoughts please!
Lots of other little bits - not going to bore you with them now. Many thanks for any replies in advance.
Paul.