I use a Flysky GT3, this one:
No major gripes other than lack of backlight on LCD.
I would however love to have either KO Propo Mars Ex-1 or Futaba Magnum. Both awesomely retro.
They'll sit in further when your wheels are sat on the floor, dead weight of the car pressing on the shocks. Currently they're at maximum extension and they're not falling out.
Touring cars have different recommended gearing for different uses (drift/race) and for different motor types (number of turns) but often these are provided in the manual with a table of pinion size vs spur size and a reference list for ideal ratio range.
People (like me!) Still use the mechanical speed controller. You might squeeze some extra juice using an ESC but for nostalgia sake I'd keep it in. I have a Mardave banger Capri with a mechanical speed controller and silver can.
I think you'd need alot of tyre additive for going brushless, mine wheelspins alot and it has a 540 silver can. I know there is brushless mardave combos though.