Hello, that may seem like a odd question. But I just upgraded my 021 with a new 250 long block. So now it is a 025. The 21 used 3/8 lp chain and I see the 25 uses the .325. I'm running a 16" bar and will say with the new engine the saw really screams. Is there any reason that I need to change to the larger chain? I still have 4 or 5 good Stihl chains left in 3/8 lp but don't want to hurt the saw. Thanks!