I love my Giannelli pipe on my Si! I have that exact one and imported it from Italy before Treats sold them.
I did not want a circuit for my Si and ended up with this but the Giannelli Fire is a nice looking Circuit for Vepsa.
Here's my Si with it:
https://www.mopedarmy.com/forums/read.php?1,3657675,3657675#msg-3657675
Had a Tecno and it's quality was kind of crappy. (edited)