as far as looking for a catback... from what i recall when making my own exhaust decision, i found a few instances where it was said that HKS did testing and found that there was absolutely no difference in hp/tq etc between axle and cat back on our NA cars so they did axle back to keep the cost of production and shipping down... again thats just what i understood, very possible im wrong here

http://us.lexusownersclub.com/forums...howtopic=55441

 

i have an 02 is 300,i put headers on it down to the y pipe and then a hi-flow cat and the check engine light came on there are two 02 sencers on the headers and one after the cat...what to i do to pass inspection