I know this is an older post but I started reading and then thinking of Vespa scooter problems vs Streetmate.
1st: Ditch the Auto Lube!!! Run 2% (50:1) pre-mix gas - the vespa system is bulletproof with gear driven and the pump is almost conected to the carb. SO DITCH THE AUTO-LUBE!
2nd Ditch the Cat-Exhuast !!! Get a real performace pipe, just use a A-35 pipe and fabricate mounting bracket. Vespa P150 has a cat right now and run fine .... slower but fine. Tomos just has a cheap/bad design.
3rd Ditch the carb!!! Get a 14-16mm sha dellorto carb (the old carb from a35 but 14-15mm) and jets to tune it.
People want something 100% out-of-the-box work right. Okay you should for good money, but the three thing mentioned about will make it a hell of better moped. Only one thing to mention is some tranny problems in the recall .... take to dealer if problematic.