I have to think that you a talking about outdoor use, so I give the nod to doubled up 2x4 boards in various lengths and batten board type corners. Speedworld in Rocklin, California and RCCAR in the San Francisco Bay Area has this setup
Otherwise, for indoor carpet racing, I think the absolute best system is to use lengths of plastic downspouts velcroed down to the carpet. Thiis is what is used during the indoor carpet season at Stockton, California. No flying cars and minimal damage if you blow a corner. It's terrific.
Constantly evolving CRC WGT and WGT-R/T...Carpet & Asphalt...All thanks to Team CRC.