I was going back and forth on buying a 309 Machine 500i or 661C. I decided to go with the 661C because of the additional torque for big dry oak trees and huge Doug Firs. I put the West Coast Saw Shop air filter kit, clutch cover, 3 Point dogs on it, ran the calibration, and was nice and easy on it for the first 3-4 tanks of fuel. I've been using both a 32" and 42" bar with full house square ground chain and this saw absolutely rips without hesitation! It is a heavy saw, but exactly what I need for the big wood. I use my Husqvarna 564XP 32" bar and Stihl MS261C 22" bar for the smaller stuff. 309 Machine's attention to detail is incredible and I'm very very happy with my new ported chainsaw! Thank you!