How old is the old Traxxas electronics? You could upgrade that with an inexpensive brushless system and have a good beater. On the street tho, it'd probably traction roll like a pig, unless you rebuilt it on the LCG chassis.

The only thing I'd caution you about a buggy is that if you flip it on the street, the shocks and shock tower are just hanging out there, no lexan body to cover it. Street means curbs too. Buggies look kinda funny with bumpers. Truggies can pull off that look better. Jus' sayin'.