yeah.. C110 has the eye holes attach to the car, and the end bolt goes through the lower arm (so upside down compared to the front)

If the adjustable strut tops are made for a standard C110 / C210 spring, then they can easily modify the setup by making an adaptor to match your upper spring seat to the strut top. IMO, this will give you a better result, as they can re-use the bearing (part No 54325). A lot of custom coilover kits omit this bearing, and it can give you extremely heavy steering, or worse yet, erratic steering weight.

As the strut tops are designed to house this bearing (I'd assume so, anyway), all you need to do is make up a spacer that mates to the top of your coilover upper spring seat, and mounts up to the bottom of the bearing.

What Stewart Wilkins doesn't know about Datsuns probably hasn't been written yet. He might cost a bit more, but rest assured you'll end up with a professional result that works.

As for something fun to replace your GTR, a friend of mine used to own an R32 GTR (with some "enhancements") and a Cooper S replica. If he wanted to drive fast (and worry about his licence all the time) he took the GTR out. If he wanted to have fun, he took the Mini.

yeah.. C110 has the eye holes attach to the car, and the end bolt goes through the lower arm (so upside down compared to the front)

OK, now I see what you're getting at!

Yes, C110 has eye top and pin bottom mountings but that has nothing to do with normal or inverted ('upside down') dampers.

Inverted or 'upside down' have the BODY at the top and the SHAFT at the bottom (to reduce unsprung weight primarily).

Mountings can be had in a number of combinations - have a look at the Koni catalogue from their website or Monroe from their site.

Koni in particular will supply their competition grade adjustable dampers in any mounting configuration you need, it just might take a little longer!

yeah... the C110 is in no way my daily driver.. that is for sure... it is a dedicated weekend / track car.. and as you say, i doubt i will do any serious racing in it.. it will be worth to much to me!

i just need something fun to replace the GT-R i sold a year ago

Should be good fun for tarmac events like Speed On Tweed, Duttons, Forest Classic etc if it's eligible.