Multiple cars on the tether would create the wreckfest he witnessed ... he had altered and disassembled his fair share of AFX ...
This difficulty in joining the 200-mph club is made more frustrating by this video, discovered by the blokes at Top Gear magazine, which shows a "toy" tether car easily crack the 200-mph barrier.
Can you spot the RC car under the mud? Re-using a jig and test track (his backyard) from another test, [rctestflight] set up solar powered tether that could power any of the vehicles under test.