Yeah I had my doubts camber would be affected but thought I'd mention it just in case lol Should be fun getting my 15x7 ET13s to fit on my GT with coilovers set low without rubbing
The only thing changing the height at the rear does is change natural camber I guess and the panhard rod setting but it's unlikely you'll have to adjust it much if at all
The offset looks quite good but I'd have gone for some stretched tyres myself with a 45 profile. Anyway looks like ET20 is ideal for EPs, not looking forward to getting ET13 to fit on my GT in the summer lol