Bacciagalupe

I had to replace the tires on my Dahon Mariner last weekend, so I've gone from the stock 60psi tires to the Schwalbe Marathons, which are 100psi tires. I can't seem to get past 90psi with my frame pump (Topeak Road Morph), and the Marathons lose air much faster than the old tires.

Is there any problem with running these tires at 90psi, or less (e.g. 70)? I know they're rated from 30psi - 100psi, but I don't want to have any major performance penalties or increase the chances of getting pinch flats.

I'm also thinking about getting a pair of Marathon Slicks, and using the regular Marathons when on tour. Anyone try a pair of Slicks on their folding bikes?

Thanks....
B