good materials to use?
 

for a grill block and side vovers for the rear wheels? i'm just experimenting to see if i'll get an increase in mpg with them or not.

for experimentation purposes, I would go with cardboard and duct tape. just for experimentation purposes though. if you decide to go permanent, then I would look into coroplast or plexi-glass maybe even rubber garden edging.

that seems to be the norm around here. the coroplast is the cheapest since most political signs are made of it. wait a few months and there will be a sea of the stuff in every suburban yard in america.

check out my garaged for a more permanent solution. it may not be the prettiest but it is better than duct tape and cardboard.

When I asked about materials, someone suggested rubber base moulding, the stuff you find where the wall meets the floor. Home Depot/Lowes/dumpsters at construction projects should have the stuff.

Another idea I came up with is discarded computers. The large sides of the case could be cut into grille blocking material. You can find plastic exteriors on some discarded computers.