EA, Even with modifications with a 2T engine, you wont get much as far as sizable gains. I had the same issue in Rome with my Honda SH-50 and Aprilia SR-50. I wanted to see what I could do to increase my horsepower, but it soon became cost prohibitive. My Italian mechanic basically told me to upgrade to a bike with at least a 150 cc engine, which I ended up doing.
Maybe I touched a nerve with Stig about the weight comment, but there is some truth to it with 50 cc engines. You might be able to swap out the 50 for a 150 on your bike, not too sure though. One of the reasons people like to modify 50cc engines is that they dont need to have a special license to drive one. Many guys I knew in Rome often put a larger engine on their bikes along with modified exhausts. Most people cant tell the difference with the engine modifications. Like I said before, this got to be very expensive for me...
Dean