I am thinking of buying a dozer and have very little idea of what size to look for. My current job will be to finish grade a job that is about 1 acre around a college building we are about to complete. I have been looking at cat d4 and deere 450 series. I would like to have a ripper but i am skeptical about the power to pull it. We have a semi so transport is no big deal. Any ideas on brand, options, and optimal hours would be great. Also, what do i look for on the under carrage and what is fair hours on the uc? Any other problem or concern areas