Go to the dealer and the on/off thing can be taken care free of charge with a software update. Once you leave it off it will maintain through future starts and you won't have to worry it about it again. If you want a nice exhaust sound trash the exhaust and purchase the M performance exhaust. Installed it's about $1700. Well worth the tone and the lack of back pressure. HP add? I don't know. Don't care. Like you the 6 is plenty for me.
Forget your Past but don't let it stop you. Tough times don't last. Tough people do.
1994 E36 Convertible (Inherited from my Loving Father)
2013 640i Gran Coupe
Carbon Black Metallic
Ivory White Nappa
Everything but B&O, Night Vision and Active Cruise Control.