Hello, i was wondering if anyone can tell me which exhaust systems are allowed in Switzerland?
I was looking for Tomei, but i read that it is not legal..

 

Suggest checking with local authorities.

Here in California, the strictest state for exhaust mods of any sort, pretty much anything aft of the cats and below a particular sound level (95dB maximum, tested stationary at various RPM) are legal. That's pretty loud. No clue what the Tomei single produces on our cars but it IS pretty loud.

Switzerland - as a quick google shows - is under EU noise regulations and therefore has a much lower noise threshold than even California. I want to say it's around 80dB max but check with your authorities.