True or Catback Dual Exhaust System

Does anyone make a good low flow exhaust system for the Xterra VQ engine, either catback duals or true duals (even headers if needs be) which is smog legal for California? My Xterra is about out of the dealer warranty, so it is time to start playing with it.

What about programmers like Hypertech and Air Intake systems?

Anyone had good luck with any of this stuff and if so, let me know.

I had an S-10 that I did these three things to and it knocked a full 2 seconds off the 0-60 time.

What about a smog legal blower for the VQ engine? Does such a thing exist?

Please advise...

eti engineer