S31? do you mean s130? well anyways, th KA is considered to be a stronger block than the SR block, BUT throwing a turbo on there without lowering compression is going to just cause a whole lot of problems, even if you tune the fuel system right. Me personally, I would stick with the L28 since its easier to turbo and have plenty of OEM turbo parts. But if I had a spare KA around I would think I would do the same thing.