I finally got round to replacing the wastegate whilst it's on the car and although the removal wasn't too bad, probably about an 75 mins, but replacement OMFG.
I started at about 2pm yesterday and finished at.... wait for it.... 8.30 this morning. I had to stop at 10.15 last night as I was outside on my back and although it wasn't raining, my hand, wrist and back were starting to ache, my eyes were getting tired and I knew if I didn't I'd probably get really frustrated and break something badly. I managed to lose for a few hours, then find one of the bolts holding the wastegate in place and in my frustration snapped one of the pipes on the N75 valve too.
I fitted and removed the new wastegate about four times in my quest to line up the wastegate arm and the threaded part of the wastegate trying using a combination of thick wires, molegrips, zip ties, pliers and three long screwdrivers. I also came to the conclusion that the threaded arm on the new wastegate was a different thread to the adjuster which was when I stopped.
Then last night after sleeping on it I had a revelation. After checking the new adjuster fitted the old wastegate arm I knew it was just me not lining it up properly.
I used a zip tie and looped it around the wastegate arm whilst using some thick wire threaded through the gap in the exhaust manifold and another piece bent into a hook to pull and guide the wastegate arm onto the threaded wire. I then used some long nosed needle pliers to pull the adjuster arm to the threaded part of the wastegate and once lined up, pulled the zip tie tight, whilst using the other hand to spin the adjuster at the same time as having a pair of mole grips hanging of the threaded arm and slightly wedged behind the power steering pump (I think) to help it line up better. This method took my less than an hour as I started again at 7.30 this morning and was back inside by 8.25.
I'd like to report improved performance but have ordered another replacement N75 valve on Amazon so will wait until that arrives tomorrow and I get it fitted. I did notice when comparing the wastegates was that the old one although there was resistance was way easier to pull on than the new one. I did start to take photos but as I got more hacked off, I stopped. I also noticed it needed a lot less turning of the adjuster onto the threaded arm and I was able to get it nice and tight without any rattle quite quickly and a lot less winding than it took to get the old one off. I will adjust it by pressurising the arm but need to check the ideal psi first as well as waiting for my hand to move without any discomfort...
If I had to do this again I could do it a lot quicker but it's up there with doing the sump drop and getting those hidden bolts out.
Definitely a job for a ramp, small hands, good eyesight and lots of luck