MOT Car Selling / Buying Scenario

[Sc0tchland]

Hello,

I had a thread a few weeks ago and looking for some opinions on my current situation. I've got a Subaru Impreza Diesel 2009 and it's seen better days if I'm honest with the MOT is due in just over a months time..

1. There's a bit of a loud rattle under load when it's cold (definitely doesn't sound like normal diesel rattle, possibly injector related)
2. It was keyed down three panels of the door by some chavs who done half the street at the same time...
3. Front left bumper needs some paintwork from someone catching my bumper in the parking lot
4. Back left bumper also needs some paintwork from someone catching my bumper in the parking lot
5. The turbo has started whistling when I change gears under load / acceleration (possibly exhaust or turbo related)
6. The EGR valve decided to choke up and was reconditioned but suspect there may be some emissions issues at MOT
7. Brake pads / discs may need to be replaced as there's slight uneven wear due to brake calliper pins seizing on one side.
8. Car has part service history

In short, I have two scenarios (as I see it) please can I have your opinion?

1. Pay for a pre-mot from the garage and see what work is required to get it back to MOT spec, then I would still have the rattling engine when cold issue and if I kept it, could be around £500 down from MOT (estimate)
2. Pay for the above pre MOT check and if not much is wrong with it then ride it out until it dies?
3. Arnold Clark is willing to pay £1500 for it in its current condition, then I could get a better car from ZX10's recommendations for say £7500?

Thought I'd ask you guys for your opinion and I can see what's the best option!

Thanks very much

[ZX10R NIN]

Number 2