RE: OFFICIAL MINI E-REVO THREAD!!!
Scope out eBay for some Foams - Foam tires premounted and truer onto the rims. You may have to search for them under HPI Nitro foams or RS4 Foams. Te same applies to searching for street tires. Becareful to note the diameter and width of the tires. Many street tires will state they are for 1/10 scale, which they are, but that's not the same as what your looking for the merv.
Generally, you'll want something as close to 2 inches wide or more as possible.
Be ready to spend at least 30 to 40 for new though.
Joe