Would prefer more than a 6 point myself! the rear diagonal provides additional safety in the event of a roll as well as joining the rear of the cage and adding aditional bracing
safety 21 cages are good, fitted a 8 point one to my mates car today and the quality/fit is good
only thing is the joins of the cage are not solid flanged joints so you could have some pivot in the joins, also the dash dodging safety 21 cages have curvey legs round the dash - not MSA compliant as this creates a slight weakpoint
this is being picky, you will of course notice a difference in stiffness and safety than if you had no cage at all.
safety 21 do some compliant cages which have straight front legs but they go through the dash, so a hassle to fit, however much stronger
best bolt in cages out there have to be Safety Devices
b-pillar loop, rear legs and diagonal are all 1 piece welded, so stiff as ****. front legs, front upper bar and door bars all fit on with proper flanged joints so no movement at all. the front legs dodge the dash but at straight and don't curve so you stay MSA compliant
IMO you want a cage with door bars and a single rear diagonal minimum. rear cross bar is not neccesary if you have a decent rear strut brace
looking at about 700 new for a safety devices
