Hi Pete.
I have an 83 GTV which has been extensively modified but is still thoroughly a road car. However, I built it with the idea of it still being competitive on the track. Whilst i'm sure everyone will have their own idea of what works best, I think my set-up is fairly normal for what you are trying to achieve. So, my specs are;
Torsion bars - 28mm from PACE engineering. I haven't tried going bigger but I never felt like I was under sprung on the track
Rear springs - King springs. These are a progressive spring that are 95-155lb. Some race cars have stiffer rear springs, around the 180lb mark but again, the Kings are much better for the street and felt very capable on the track. Plus they are fairly cheap.
Bilstein B6 shocks - these are fantastic and I prefer them to Koni's but I know many are very satisfied with the Koni's so either way.
PACE upper ball joints - these are essential to improve the roll centre issue with these cars and well worth the extra few hundred.
A/R bars - I am just using stock 75 TS bars at this stage (slightly bigger than yours) but plan on installing an adjustable rear bar in the future. The front is 22mm and the rear I can't remember! That said, when I used stock road tyres I removed the front bar whilst on the track. Track tyres would be different.
Finally I used a mixture of rubber and poly bushes but mostly rubber. The only poly I have left is watts linkage and rear A/R bar drop links.
As far as roadworthiness goes, I cannot see any reason why your roadworthiness should be affected by these modification except for ground clearance (depending how low you go) and maybe the upper ball joints but I'm not sure about them.
The only don't I would say is go crazy with poly bushes. Maybe for a dedicated track car but otherwise you will have far too much harshness for road use.
With this set-up I drive it as a daily and am quite comfortable, plus it is a fun drive to work! The only issue is speed bumps as I have lowered it.