I think the wheels are the standard ones from a Skyline or Infiniti G35 and are the same sizes and offsets as the standard 350Z wheels so should fit no problem. Tyre sizes should be the usual 225/45R18 front, 245/45R18 rear although those odd sizes might work.
I agree though, way too expensive when Rays can be had for a lot less.
The 370Z Rays use a flat seat nut. I think the Nissan part number was 40224-JK00A last time I looked into it, no idea on price though. If you want locking nuts then they're Nissan 999W2-JT000 or McGard 21153.
I've run those same winter tyres for about 4000 miles over the last three winters and I've found them great in snow, ice or just cold, damp and slippery. Mine cost me £666 if I recall so these are an absolute bargain.
The grey (they say it's silver) one in Burton isn't rev-up, the rev-up would have the newer headlights, rear lights, front bumper and interior of the HR but without the bonnet bulge. That Burton one has none of those things.
The high tax kicked in on 23 March 2006 so a few early 06 plates will be in the lower bracket. I just checked the vehicle enquiry page and that grey one was registered on 15 March so you're in luck.
When I was last looking for a 911 about 15 years ago I went to see 911Virgin, seemed like a nice guy but I was really put off when he told me he'd clocked a yellow 911 to help it sell as high mileages put people off.
I presume they've moved on from that and are now a more honest and professional business?
A 275/40 tyre might look a little chubby for your needs then so go with 245/40 and 265/40. If you want some stretch then 235/40 and 255/40 should also be fine with the VDC but would make your speedo out by a bit more than ideal.
Don't know about those, they're suitable for 9.5" wheels but otherwise quite small and similarly sized.
I'd say that you'd be safe with 245/40 front with 265/40 rear or 255/40 front with 275/40 rear. Both would retain a similar front to rear ratio and overall circumference of the standard tyres and be suitable for 9.5" rims. Would depend on your offsets and how low you are though.
Unfortunately it's 2cm too long to go in the post and a courier is going to be around £10, so even at £20 I'm only getting £10. If you'd like to collect then you can have it for £10, can't say fairer than that.
This was the thread I was thinking of which goes through some refinishing options:
Rear Strut Brace Bar Cover "Z" Badge Solutions
Post #46 shows the logo repainting, looks like you'll have to sand it down to get the old finish off.
I'm sure I've seen a thread where someone refinished the Z in something that looks similar but was more durable, that may be a better and cheaper option for you.