is this thread just a free-for-all or what?

any ideas on how deep i can have them combined with it being lowered with out any arch mods or rubbing?

deep - not very on standard 1.2 brakes unless you get splitties or a low offset.

lowerage and rubbage - depends on what tyres you use.

arch mods - see above referring to offset of the wheels and tyres.

I'm all the way down on v-maxx coilovers...9 inch at the rear with an offset 15 barely any rubbing.