Kevin, you can check out my M925A2 for yourself to form your own opinion. The 1400s are plenty big and meaty. I think you will go with them when you see how great they look on my truck. You have a multitude of choices but basically it comes down to this...do you want to keep your truck looking like it might have looked in service, or do you want a truck that looks like a monster truck? If you want the former, stick to the 1400s. If you want the latter, step up to the 1600s. The 1600s will give you more road speed, that is true. I have no idea how fast you'd be able to go. I do know that the 1400s allow an M939 series truck to drive at 65 mph. Who needs to go any faster than that in one of these trucks?!?! I wish RAM were still alive and Joe Young still frequented this site because they both would be telling everyone that these trucks were not designed to go faster than that.