Lowering Springs

[E63 56]

I’m keen to get lowering springs for my E63 to reduce the glaring arch gap.

At the moment I’m running ET34 and ET39 with 20 and 25mm spacers. The wheels protrude nicely close to the guards.

Is there an intelligent way to test if I can lower by 20-30mm? Or do I just need to chuck the springs in and go for a few drives? If it wasn’t an E63 I’d be fine with buying and testing, but may be difficult to resell the springs if they don’t fit safely.

Intuitively, any rubbing seems dangerous. Is this true? Those of you with slammed cars and tight fitment, can you turn your wheels all the way, or do you loosen your turns to stop rubbing?

I’ve seen E63’s on 22’s, so maybe it won’t be a biggie..