or should l wait till next inspection? where would be best online store to buy catalytic converter and other parts to modify my car?

google magic my friend. SEARCH. l use alot of different sites to not only gain knowledge about.but also to compare prices. look up forums for your car and read them and gain piece of mind. Im lucky l dont have inspections where l live. l dont have a cat on my car.its performance driven.

If u r having signs of catalytic converter failure, such as a ''rotten egg'' smell, idle issues, or stalling; u need to replace them ASAP because u have a turbo.

A clogged cat in ur up pipe can cause extreme heat temperatures to enter the spool & turbo assembly, cooking the oil to the bearings & eventually blowing the turbo. The air heats up because the friction increased to get through the clogged cat.

The cheapest l can find OEM cat is is at:

http://google.com/products?q=2002+impreza+catalytic+converter&ie=UTF-8&oe=utf-8&rls=org.mozilla:en-US:official&client=firefox-a&um=1&sa=X&oi=product_result_group&resnum=1&ct=title