well.. this is getting ugly.. and it's all because of that air filter. I assume, since i see nothing to the contrary, that you have a bone stock bike except for the filter.
Mopedwarehouse notes that rejetting will be required when using that air filter. But without upgrades and modifications elsewhere in the engine / exhaust you aren't likely to see any performance improvement. Modifying your bike to accomodate that filter is a waste of money and a needless headache, imo.
I suggest you find a stock air box and filter.