I enjoyed my use of the Yoke 032s but found their wear rates comparable to the Victoracers. They are better in the rain/wet however. And they are a very noisy tire.. lots of "howling" and that's in a straight line
I just moved up to 16"s last year after a decade of 15" wheels and find I am also limited.. 205/225/245 widths seem to be all there is.. same as for 15" wheels. 17"s will get you a few more widths.. 235/255/275/285 and up to 315... mmm steamrollers :P
17's are something to consider, especially if you have turbo flares. Any number of wheels can fit.. aftermarket or the newer offset Porsche wheels. If you currently are running 7/9 x 16 Fuchs, you could easily sell them and buy a set of 993 17" "cup" wheels to bolt on.
Any tire, when at or beyond its limits will get greasy. R compounds simply get greasy at a higher point though.
As for the Khumo MX's I remember hearing horror stories when they first came out.. tread separation, chunking etc. Maybe they are better now.