Well in my case it's very hard
I brought a new turbo a few weeks ago and started to fit it the day I picked it up.
Got most of the pipes off and a few of the manifold bolts then realised that the new turbo wont fit with the rouse manifold and exhaust
So I put it all back together and went on a search for a standard manifold and normal exhaust.
Got both items last weekend (Thanks Spadge and Spiky) so I booked some time in my mates workshop for this morning to fit them.
Got the car in the air and the exhaust was off after about 10 mins
All the pipes were soon to follow
Then SNAP. there goes one of the manifold bolts ' bugger' then another SNAP

luckily I had a few spare ones so i wasn't too concerned.
started to fit the new turbo and very quickly realised that I wasn't gonna manage it. NONE of the oil or water pipes fit. Feeling rather pissed off I had to spend the next hour or so refitting a turbo that is only good as a door stop until I can get the replacement pipes.
So now I am back to where I was this morning with a car that dumps over a litre of oil into the exhaust every week whilst making a dodgy police siren type noise.
I should hopefully have the new pipes early next week and fingers crossed have it all fitted next saturday