Car looks great mate. Great buy!
I would have the inlet valves cleaned manually, it'll do far more than Terraclean ever would, trust me, I've had both and I doubt they've been touched in 90k.
As others have said, iridium plugs are the way forward.
As is V-Power or Momentum. Basically 99ron fuel and a very sound piece of advice being replace the cam follower lobe. VW say the fuel filter should be a lifetime part, but that's BS as many of us know.
Check for boost leaks, but I'm sure the diverter valve will have seen some stick. It's up to you whether you go for a revised OEM one or an aftermarket part like Forge.
I personally use Mobil One 0w40. I have done for 70,000 miles. It offers better cold start up protection than any other oil and better viscosity than any other 5w oil.
Of all the flushes and I must have tried half a dozen, nothing does what it says on the tin quite like Forte Advanced Motor Flush. I change oil filter and plugs every 3k and every 6k I run one of these flushes. Also the PCV breather valve is a naff design, VW did do a revised edition, failing that you can pick up BSH or Forge ones, I've had the former on my car for 60k and it sorted a very lumpy idle, as well as aiding boost issues.
Hope all that helps.