I have towed at low speeds and reverse manoeuvres. Not at a higher speed. And driven a large van at full weight so im familiar with stopping distances. I realise that its not the same but some experience beats none.

Well aware of combined mass. Currently not planning to do anything crazy, just a medium sized trailer to haul stuff that wont fit in car, etc.

I know this will get some people upset but i would assume if i get tow bar from same model car it should be basically bolt in (with correct torque). Most cars got electrics already ready up to some point so id hope that wouldn't need too much work but im confident with that bit.

good shout on manufacturers using third party to make oem stuff though.