A Ford Escort to be competitive really needs a 1600 engine at 100bhp plus. And Jacked up a bit. also needs a Fack or similar Strong Diff put in.
A Midget needs to be well tuned (1275 or 1500) jacked up with a stronger diff. An Austin A40 Uses the same engine and drive train as a 1275 Midget so the above applies also.
I campaigned a 1275 Midget many years ago and always took two spare diffs and half shafts plus equipment to change them. This only added to the weight and sold it after only a year and a half. (Bought a Beach Buggy).

I also used a 1300 Escort for a year until the MK 2 Midge was ready. Totally under powered. hence a 1600 needed.
Possibly someone that still trials one of these cars may have more modern solutions, however the dwindling numbers of these cars competing shows that other cars are possibly better and or cheaper, unless you are prepared to put a lot of effort, modification and cost into such a vehicle.
Those that are still successfully competing may look fairly standard but are well modified and tuned.
I somehow think that the German TUV or such regulations will get in the way if being built in Germany.
Hope this helps.