Replying to Fellow Car Enthusiasts....a question

Before anyone laughs, I would like to acknowledge that I am aware of the fact that I own a 2005 Honda Civic, and am aware that modifications are nearly pointless.
     THAT BEING SAID.....
I am looking for a reputable site to pick up a few parts for a Decent price, mainly a couple things to improve performance at minimal cost:

Front Sway Bar (the piece that connects the spring studs under the hood)
Quality Wheelbase Wideners (aka Spacers)
A Catalytic Converter (my stock one is nearly rusted through, I know this can be a bit pricey)
A Cold Air Intake (<$200)

For Anyone Wondering, the vehicle is entirely stock minus some quality spark plugs, I do not own a ricer.