I do like the look of the b12 kit, demon tweeks have a few to fit the GTi but different prices and all labelled ‘b12 kit’ so unsure what the differences are! Albeit abit pricey fir a road car that will see occasional track use! Debating on the h&r cup kit, awesome has it for £580 atm! Anyone used it before?
Yes it's confusing.
B12 just means B8 dampers + some springs.
If you want ride comfort and mild lowering, you need a B12 'Pro' kit for a MK6 Golf.
If you just get a B12 kit for a MK5 GTI, you will get the B12 'Sportline' kit which is waaaaay harsher and lower.
The easiest way to spot the difference is:
Sportline = red springs @ -30 to -40mm lower than a GTI
Pro = black springs at -25 to 30mm lower than a non-GTI
Since non-GTIs are 10-15mm taller than a GTI, the final lowering of a GTI with Pro kit would be approx -10 to 15mm