Wanting to upgrade from a JD 450 C

I now have a JD 450 C. I have owned it for about 20 years. I would like to get a little larger in weight and HP than what I have now. Probably about a JD 550 or a Cat of similar size. I want a 6 way blade. I am in the Texas Hill Country so I don't need a LGP. Used for pushing cedar and building small ponds. I probably put less than 200 hours per year on it. Question is: I am wanting to spend around $40,000 for a used dozer. What model of JD 550 or Cat of comparable size could be purchased...

Wanting to upgrade from a JD 450 C

Wanting to upgrade from a JD 450 C