As I said in your other post, they is no such thing as "high-flow" cats. They are just smaller cans with less substrate/honeycomb catalyst which makes them less restrictive; and not last as long because they are improperly sized for the engine.
25k to 30k is about it before they stop scrubbing the exhaust.
- 2003 GT, UPR X, FRPP 24lb/h, Magnaflow, PP 70mm TB & plenum, Delta Force tuned,
Steeda UDPs, Ralco flywheel, RAM HDX clutch, 3.73s, 262 rwHP/305 lb-ft.
New ride (7/1/2013) 1998 Mercedes SL500-5.0L 32V VVT 326/347 HP/tq