Here's my thoughts , My 240z has a tweaked L28 with triple DCOE's, S13 gearbox, Subaru R180 Quaife LSD, some R32 GTR front brakes and some oldskool bucket seats,
I would call it a 'RestoMod' because its all 'under the skin' really and still looks pretty standard at a glance, but with modern upgrades that help improve/modernise it a bit.
I started with a standard 240z with no engine and put my 'built' engine in there and converted it from auto to 5 speed manual after replacing both floorplans, rear arches and some other little bits and then drove it standard while I ran the engine in, but soon I started tweaking bits, better anti-roll bars, then brakes, then rear 4.11 CLSD ,then gearbox, then upgraded the brakes again , then changed the diff to a 4.44 LSD, I've probably forgot some bits along the way to , But it was a good process to go through as I did get to feel what each upgrade improved,
My advise would buy the best base car to start with , if you cant weld or do most of the work yourself its gonna cost, and cost a lot...
I don't worry about LHD but some people do and it must be RHD or converted , which will cost, 6-7k to 10k ? 'Most' LHD cars are less rusty so will save you some work/money if you can live with it , and if you ever do a Europe trip your on the right side.
There's always the question of if you ever want to sell it to and get some of your money invested back. A standardish car will probably be worth more than an all out 'restomod' with patches, stick on arches and a 2JZ , with maybe a tastefully modified one somewhere in the middle ?
Anyways here some photos of it
At the end of the day built the car you want and don't (well try not to) worry about the money...