It's not just for braking mate, bigger arb and wider track as well. Also bigger torsion bars iirc! My old comp brake did that, although it's only minor, it's an annoyance, never had that problem with the b&m style one, and I've had the grub screws come loose when using that kind you have and changing gear was a hassle for sure! Did you do a full loom change or just the engine?