cold air intake and true dual exhaust (2 pipes all the way back). how much hp

[Matt]

and torque gain do you think? i have an 05' G35 Coupe 6MT that comes standard with 298hp and 258 lb·ft of torque. I added on a K&N cold air intake kit and installed to exhaust pipes from the engine all the way back to the 2 mufflers in the back with an expansion box on each pipe to reduce a little noise and vibration. How much hp and torque do you think im pushing out now? Don't have the time or money to do a dyno test. Just want your guess.