Good questions. I didn't ask them about cost, but I'm sure it varies according to stroke increase.
As for power increase, man, that's a tough one. A really wild guess by me would be somewhere around 10%, but, that's from idle up to max revs.
The main idea is to do the stroker crank in conjuntion with a big bore kit, maybe bigger carbs, and possibly bigger camshafts.
The big deal is the torque increase, which should mean that one can run the biggest counter shaft sprocket and still pull Mama and loaded saddle bags up a Colorado mountain.
