Please check the Forum Guidelines at the top of the Newbie section
Sorry, I seem to have been blind for a while
Yes, I can still help with this. Is there a particular date that would suit you?
https://www.omegaowners.com/forum/index.php?topic=124057.0
This I found.
Even my mechanic didn't believe you could change just the valve until I showed him the pictures from this forum 
How does £125 to do all that sound, which would include a rough and ready alignment to make the car at least drivable.
Hence I always suggest people with GM ones refurb them, rather than replace with crap. Its a bit extra work, but cheaper and will last longer.
Is there any easy to spot tell tale that they are original GM? GM logo somewhere?
They'll look like they were rescued from the Titanic; rusty and covered in crap off the road. You're getting bogged down in details that are unimportant.
You've got new wishbones, so fit the front poly bushes and get them on the car. They'll be an improvement. If the removed ones look vaguely saveable, keep them. If they don't, bin them. To me, the only thing the originals do better than refurbished ones is that the ball joints are rivetted on, not bolted.
Hence I always suggest people with GM ones refurb them, rather than replace with crap. Its a bit extra work, but cheaper and will last longer.
Powerflex... Drill old ones out, then cut the metal holder being careful not to slice the wishbone, remove old ball joints, bolt new ones on, remove rear bush same process as front, and replace with new rubber bush.
The self leveling shocks firm up the rear end so GM fit softer springs to compensate.
The result will be akin to driving an old Cadillac and it won't help the life expectancy of the new shocks.
The front springs are the same for each engine type but there are variations according to the model... ie police/sport/mv6/Elite.
as nick mentions it wouldnt do any harm to purchase some but not nesesarlily fit them yet.
if the rear springs are indeed selflevelling versions and the self levelling is not working then you would expect the rear of the car to be too low as it is now. or even look not too bad unloaded but be way too low with any passengers in the back ?
if the rear level is good however then it suggests the rear springs are std versions. ( maybee aftermarket that just happen to have those letters printed on ? )
springs dont physically "wear out " as such but can become weak over time and the indication of this is a drop in level . a spring cannot technically become weak and stay at the same height.
same scenario with the fronts. if the ride height is correct then the springs are good. yes they could snap tommorow. but so could a new one too !
That's a very kind offer to do the work, and I'd be more than happy to assist in any way I can. Do you have any recommended brands/suppliers for the springs/top mounts/bump stops? I'll try and do some shopping and get all the parts together in the next couple of weeks
I've never found any benefit in worrying much about brands for car parts, although there are few I won't buy due to limited, anecdotal experience. It's really easy to waste lots of time searching some ultimate part recommended by a stranger on the internet....
I bought all four springs for my car from ATP for less than any of the UK suppliers wanted for one estate rear. All quoted delivery dates as to be advised. The ATP order, which included some other stuff, arrived in three days.
ATP no longer seem to list the top mounts and bump stops which is a pain, although various UK supplier do with the usual variance in prices. I would buy them, including the strut bearings(sometimes included with the top mounts, so be careful), from a single source who could supply them all.
Given that your rear springs have probably been replaced recently, I suggest that new ones should be considered nice to have instead of just change them. Polyurethane wishbone front bushes are essential, whatever else you decide to do. Some careful shopping should get all the parts as discussed for under £200 per side. This is not a cheap job, but will make the car drive like new.
