I've bought a used engine from 2008 that didn't had to much milage in it, I've pulled everything apart anyway though. Better be safe than sorry when you'll make the engine perform more than 100% of what standard specs are :)
I'm running :
Darkside Developments hardpipe kit
Darkside Developments TIP kit
Darkside Developments S3 intercooler
Darkside Developments turbo kit with downpipe
Darkside Developments AEM airfilter kit
4bar MAP sensor
Firad nozzles
All my engine parts has been vapour or soda blasted, new seals, new filters, new screws/nuts/bolts, new piston rings, new tandem pump, new water pump, Forge motorsport coolant hoses, new fuel hoses, new cambelt kit and all that
Really looking forward to this engine is installed to the car and mapped :D
Maybe I should look into converting it to a 4motion if it's possible to find the parts to a reasonable price somehwere when I'm doing the DSG convertion to next winter hehe