Anybody selling a ITR cat? and how much? have an 01 GS with cheap 2.5" highflow cat. Thinking I should downsize to 2.25". I think the ITR stock cat is 2.25" and would be better sound yet still pass the inspections easier. Have new front 02 sensor installed, rear 02 sensor has a adaptor/spacer on it. no check engine light. inspection passed that way. and what are your suggestions for headers and catbacks for performance, nice low profile exhaust note, legal.