I don't think there is an aftermarket cat that will prevent the CEL. I have the SOLO hi-flow res-cats on my car (no LTs - just the mid-pipe replaced). They were billed as no CEL. That was true for about the first 10,000 miles. Since then I get a CEL (cat inefficiency) every 60-80 miles. But that's OK, now I have an excuse to get LTs - might as well get the added power & sound now if I have to deal with the CEL anyway.
