Hehe, i had almost the same exact exuse about a week ago. We got a few fat oak trees to chop into firewood. The largest 2 have about 50" dia in the bottom, and i have to slice them up to about 40cm pieces.
We (my father and me) had jonsered 625 but we asked our neighbor to help us fell the trees. He used to do that for a living and is using a ported 064. And oh boy what a difference does a chainsaw like that make when you really bury the bar into the hardwood. Luckily the brake on the jonsered started crapping out again and it was the Sign.
I went and picked up a mint condition stihl 046. Now im trying to find an excuse to get a bigger bar, because im not sure when its going to see any trees of that diameter again. But i think a 24" would fit nicely on this chainsaw.
Heres the pics of the oak and 064 with 20" bar.
(PS: now i need something in between my 046 and 170 )