Yes Sootacars are noisy. Two reasons. The engine is near enough in the car, the passengers sit on it. But also there is minimal sound deadening. The body itself is going to drum and sound proofing it would add a lot of weight. From memory the 3T was quieter as it is a balanced engine and the blowers do act to pump some of the noise away. Maybe the exhaust was more efficient than the Scootacar I drove which had a home made system. AS far as I am concerned this is perhaps the main critisism of the Scootacar.
Handling - Well it stops as it has hydraulic brakes, so you need the best tyres you can buy, which seem to be the German Hedineau. Armed with tyres that grip I suspect that like most folks the surprise is how well the thing goes. Little wheels find bumps. The front suspension is a bit simplistic but I found I could make it work well, maybe my over average weight helped. A Scootacar produced well will give a Schmitt a fright. A Mk3 has little competition, Goggo 400? Be quicker I think, as its lighter, same with Vespa. Either way these are usable cars, the more so as eccentric second cars. They have a lot of space inside, its just not really offered in immediate to use form. A few hooks and bungees and stuff can be stowed back. So great for shopping.
Price, what can I say. They have gained price nearly exponentially almost. Partly as there only so many to be had. Having sold mine I am resigned to never owning another as the price will probably continue upwards well beyond an amount I am prepared to pay. But then I can remember not making enough effort to get Dave Floyd's cars off the Scrap heap at Haynes. The days when £25 would have made a difference?