is a trd exhaust worth the money for my '06 scion xb? what about the trd...

[james]

...filter? how are the power gains? i was offered the exhaust for $100 and the filter for $25. the exhaust is used and the filter is new. should i save my money and get another system or should i be jumping all over it. this is the first toyota i've owned. always driven hondas, but decided to explore outside of that realm...any opinions on the hotchkis tvs stage 1 suspension kit? trd springs and struts? any info is greatly appreciated.