I was just wondering what MPG others are getting with pretty basic bolt ons. I am getting about 15MPG and sometimes lower in my 2008 MR with the following mods:

K&N Typhoon intake and UICP
Turbo back exhaust, I believe my DP is an AMS w/ high flow cat and HKS Hi Power cat back exhaust
Some generic cheapo BOV
Boost pill is removed (none at all)
I am running a "protune" via Cobb AP

I suspect this may be the reason I am getting bad gas mileage as the shop that did the tune is less than reputable. I also occasionally have pretty bad backfires in between (notable 1st to 2nd) shifts if I let off throttle just before the shift. The backfire occurs during the shift usually.

 

I run hollywood_x tunes for years. On my MR, I get 18mpg on gas and 21 mpg on E85. I'm running HKS/Fujita intake, dp/test pipe, HKS catback, 1000cc injectors

 

2014 gsr
stock air box
High flow panel filter
depo UICP and UICP Elbow
depo down pipe
depo test pipe
RRE stealth sideways catback
AGP FMIC
Cobb EBCS
Cobb AP (running the Stage 3 map that I have been tweaking)

on the highway I get 26mpg on longer drives when driving easy. 20-21 when driving aggressively on the highway

city is anywhere from 15mpg to 18mpg. City I live in is not really flat and can have bad traffic.