If you want a lot more usable torque then you should get rid of your heavy stock x-pipe and swap for a titanium catless unit. Should run around $1,500 installed. Car will be lighter by ~ 50 lbs and you will gain 20-30 lb ft of torque throughout the entire rev range.
Daily: 2013 e92 M3 DCT / ESS VT2 650 S/C / Akrapovic Evolution / StopTech BBK
Track/Airstrip: 2011 997.2 Turbo S PDK / GIAC Stage 2 (9 second file) / Ohlins coils / R888's
Beater: 2013 X5 3.5sport
YouTube Channel: https://www.youtube.com/channel/UCT1...eoFBszPIK0gf9w