I agree with the comments below. Have you ever seen Jim at a pull? He spends more time studying the track and going over his setup than probably 95% of other pullers. I met him at Tunica and have seen his tractor pull to victory there two years in a row at two different weights and speeds. That is a VERY difficult and amazing accomplishment. I have also looked over his tractor and noticed it was well compliant with the rules.
Right now Jim Benjamin is like the Michael Jordan of tractor pulling. When Air Jordan won 6 championships on the basketball court, do you think the other players in the league thought he was a cheater? No because Jordan spent the time to become great at the game. He would even practice free throws after games that he won, simply because he had the drive to be better. My point is that greatness of this magnitude should always be looked upon with admiration, rather than jealousy. There seems to be lots of guys out there who think if they never touch their tractor between pulls or make any adjustments at the pull that they should be able to show up and expect to win. You can't expect a full pull without fine adjustments any more than you can expect a 3pt buzzer beater without practice. Anyway, think of how many kids Jordan inspired with his drive and commitment to the game both on and off the court. I hope there are youngsters who are saying "I want to pull like Jim Benjamin". I want be in on the t-shirt royalties for that one. :-)
Now for the more technical stuff. The tractor is listed at 525 cubic inch. I've seen him beat much bigger 6 cylinder MM's in the 7250 KOH class. That folks is called tires, weight balance and driving. The tractor is amazing and so is his driving skill and balance intuition. In my opinion, a tractor of that caliber is worth the money and the chance to talk to the seller during the transaction to learn how to properly pull it would be priceless.