Neil (singlespeed) is running a stable 160+ bhp with a high of over 170bhp. That's probably the highest someone is putting out in a 133.
I know Joe is using NOS on his 133 but I haven't heard much so I guess it's either less than a 50bhp shot or he's sold it before he got it full set up.
But search around as there's a 225 engine in a twingo on here, a 182 engine, and a 197 engine in a twingo on this forum.
An engine swap is the cheapest per bhp