So installing a Boss manifold lowered your RPM at cruising speed? Alrighty then....
Engine is not working as hard to hold 70 mph, rpm's are down at 70 75 80 is a characteristic I have observed post Boss. If its just me than me and not the boss then hats off to my tuner, freakin nailed it and he has his dyno dialed in. Car is also quieter and drones eliminated I keep winning with this boss install. Its jumping to the top of my favorite mod list.
15 F22 M235i, JB4 Stage II, Cat delete, CAI
12 GT Prem 5.0 (Sold)