Buy a dozer or a new mini Excavator

Ok y’all,
I have the chance to buy a old 1984 450D dozer with pedal steer for 8k-9k it’s in good condition or do I save the money to put towards a brand new YANMAR ViO50 mini Excavator with a cab spring summer 2020 to replace my Takeuchi tb135. The excavator I use 80 -90 percent of the time and is the bread and butter for my business. The dozer I would uses here and there on finish grade work and some land clearing. I’m torn because it’s not every day u find a deal lik this.
Let’s here some thoughts !!!!

If you buy the dozer will you start taking work that you didn't before because you didn't have a dozer

Does your current mini need replaced because its worn out or do you just want something newer for reliability

Dozer.