Different front and back tire. good idea or not?

[sudapuff]

so its time to put some new tires on the bike and i was wondering if i should put kenda K657 130/90 on the rear and kenda K671 100/90 on the front (because the k657 don't come in a suitable front size) or should i just go with both front and rear K671.

the k657 and k671 are the same price so thats not an issue but i was wondering if putting the "sportier tire" on the rear would improve performance or impede it.

also if you have any other suggestions for a tire let me know. i commute about 120 miles a week, only push the bike every once and awhile (even then im a very cautious rider), so performance is a benefit but not the ultimate goal. im more looking for tire life and price while still improving on the stock tires' handling and performance.