I contacted Brinkworth this summer to get an idea of the price as it seamed more affordable than Pandem and It was, however the question is should you.
As long as there has been Z cars there has been body kits the early ones were the G nose, and ISMA these were meant for racing but undoubtedly found there way onto the street on Japan and USA. Fender flares like ZG have been around as long as the hills also but modern twist is some are made from carbon fiber and this can be matched with carbon fiber bootlid and carbon fiber rear bonnet.
The style in the UK has always been on the modest resto mods, large body kits may date quickly, but the lines of a classic historic car always lasts. My option is that if the car is badly rusty, you could consider it for a bit of fun with kits, but if the car is good perhaps a historic restoration is more appropriate. I think as the 240z is a small car its too small for a large kit, it just looks wrong the longer wheelbase of the 2+2 may suite a larger kit and as the members on this forum are less sensitive over the 2+2 perhaps an easier proposal to swallow.
Please bear in mind that Brinkworth flares will require 10.5" wide fronts and 12" rears, these are expensive, these will require power steering and they will destroy the handling.
240z's do bounce fitting large tires will turn it into a trampoline without making significant adjustments to suspension and dampers. As the center of tire has pushed out your wheel bearings will take an absolute thrashing on the outer edge and likely to need replaced every few ten thousands of miles or so.
Also consider how may times you will be pulled by the local police for them just to check you out, and every local ned in their corsa wanting to drag race you from the lights.
It is likely that if or when you resell the new owner will wish to change it back to stock and reduce the price accordingly, this can be seen from a car that was prepared for a TV show where they spend £60k and put on ebay and the highest price was just over £10k.
If you are looking for a street car and you have considered the above, and you are looking for a bit of fun and can afford to lose the money please carry on, but post photos on your progress.
I think mine will end up looking very similar to the Gas monkey 280z, I would like to use 16x9" works CR01's with toyo r888r tyres. I was considering a paint job similar to the old 240z pace cars which were blue and white rather than red and white race cars, but perhaps I'll chicken out and go for the original metallic blue.
There are countless options and I would suggest you do plenty of research. Perhaps another option is to adapt fenders intended for another car?
I have never done this or hear for anyone who has but I understand FRP can be adjusted.
https://www.ebay.co.uk/itm/FRP-FIBE...680563?hash=item3d24e03d33:g:QIEAAOSw9IpXzl8R
I am sure there are more knowledgeable users on the forum who have more knowledge and I defer to their knowledge and corrections.