Wow, those are wide and low for a Spider
You might have to experiment a bit to see what works for you, don't forget the cars were designed when 70 aspect was a low profile Tyre and 165 was wide. A lot of the ride quality was gained through deflection of the Tyre, so reducing the profile will make the ride quite harsh. If you run them softish, it will help, but then the steering will be impossibly heavy. I'd try at about 30psi and suck it and see.