any good working used 6.5 usually about $35-40 shipped...
Any motor will eventually need a set of bearings, & they always need a occasional drop of oil on the bearings.
I have a couple of old LRP X11's that have been rock solid.

An ESC with a touch of boost or turbo & watch motor temps & sky's the limit.

I use 4pole motors in my 4x4 SCT's...