One of the best upgrades to Trad brakes is to use Aeroquip hoses all round. It will give a firmer pedal.
I would be wary about fitting larger front brakes and calipers unless you have a real fire-breathing +8 , as the 4/4 and +4 are slightly "over braked" as standard, and can be made to stop extremely efficiently.
For competition cars like the Roadster or +8, the issue is one of solids discs that warp under heavy, continuous and high loads, so vented discs make sense. Unless you are driving really wildly on the road, you will never need them.
Also forget using disc brakes on the rear, again unless you have a true competition car, it is just not worth the effort, and the handbrake becomes tricky to keep functioning efficiently.
Andy
