What I would do, personally, is get a set of HPI Super Nitro 2.2" sedan wheels, and a set of 2.2" 1/10 buggy tires (REAR tires)
check out this combo, should work great for general bashing:
wheels:
http://www2.towerhobbies.com/cgi-bin...&I=LXMX92&P=RF
tires:
http://www2.towerhobbies.com/cgi-bin...?&I=LXDX75&P=7