I'm nearly finished the catback install. I went from stock to 3 inch Flowmsater. Still needs 2 tailpipe extensions and a couple of leaks sealed up. I had it up and running last night and I noticed the exhaust smelled really rich. I haven't pulled the negative from the battery yet but I'm wondering if the fuel pressure may need to be lowered too. Also, the idle stayed around 1000. Possibly because freer flowing exhaust isn't warming the 2 wire O2 sensor?

 

It shouldn't

Way back when I had my exhaust overhauled I noticed nothing that suggested my engine was running rich.

The idle may hover at a slightly higher rpm for a bit, especially when slowing down. I think its because the engine compensates for the increased airflow.

Try resetting the prom and checking the O2 sensor to make sure its not fouled.