Help with Dynojet Research Power Commander V 25-004

[woodtouch6]

I recently installled an sftermarket exhaust on my 08 GS SM5 and it runs pretty darn rich. Also my fuel mileage has went down to around 26-27 Miles/Gallon.
Has anyone installed this
Dynojet Research Power Commander V 25-004

if so what was your experience like? Did it help?
Thanks,
Craig
SW WA

[NancysToy]

Installation of an aftermarket exhaust normally makes a Spyder run leaner, not richer. Are you sure you didn't introduce an exhaust leak pior to the O2 sensor (bad Y-gasket) or damage the O2 sensor or wiring? Get the exact cause and symptoms pinpointed before you try an aftermaket fix that could compound your problems.

[spyder32]

We had it installed and the difference is amazing. Better performance, better fuel economy and it actually lowered the rpm's at the same speed like an extra gear!