T Top Infill?

If less weight is a priority why choose a 2+2?

Steve Mitchell was probably the first to do this back in the 90s.

No 2+0's available either, all T top 2+2's. But for circuit racing the longer wheelbase 2+2 may be better anyway, going to use S14 suspension and the S14 has a wheelbase almost identical to the Z31 2+2.

Be careful with s14 suspension, rear free length is way to long for the z31.

Someone (you?) mentioned that in another topic I noticed, handy to know. With the S14 conversion for the 280ZX I got custom parts made to suit the ride height required, because race car.

After considering the strong T roof structure Mr Nissan did, I think a length of curved to match the roof line RHS welded across and above the door opening will do for the structural requirements, particularly as there will be roll cage bars running along the top of the door openings too. They will be tagged to the RHS as well to combine the two as one for extra strength. These 2+2's have wide door openings and so need to a lot of support above and below those openings to minimumise body flex. The A pillars don't look relatively strong but once again their strength will be boosted by the cage.

As for the infill itself, using the glass tops as moulds for made up fiberglass panels should work. These can be bonded into place all round. Any constructive criticism on all this is welcome.

Probably. Brian is the original one who adopted by raising the rear strut mounts.

s13 rear strut assemblies (OEM and aftermarket) are much more favorable to the application.