the overland and racer chassis's are completely different, so no, you can't use the overland suspension.
there any any number of aftermarket wheels that will give a racer slightly more ground clearance and traction...
see me , the same person also used lego tires...
the use of larger tires will require body modding though. what has been done and looks good is modding 1:24 05 1:25 rally bodies onto the overland. look through
here .
that is a nice choice! the imprezza is sweat looking! what it comes down to is, you can take your imprezza off pavement so long as it is very flat and hard packed, which clay usually is. there are some mini z scale agrressively treaded tires that don't require any body mods but you'll have to hunt them down. the stock slicks will suck offroad. gpm makes some treaded tires... it sounds like your sold on the racer...you'll like it! i love mine, i have the cr5 body and it is sweat!