What's the widest I can go without arch mods

[16v]

Hi,

On a 90 Mk2 16v what's the widest wheels I can fit whicle keeping the standard arches, ie not rolling.

At the moment I have the OEM suspension but am going for coilovers with about a 30mm drop. Don't want any fouling with weight in either.

What offset would the wheels have to be ?

Thanks in advance.

[Agreeable Slick]

7-7.5J at a push i reckon.