My 2000 Monte In Progress

I wouldn't reccomend running the 2 different subwoofer sizes. i spent 4 days with different box sizes, crossover points, sub sonic filters going crazy trying to get it to have an un-noticeable transition between the 12's and 15's my customer wanted in his F-150. I had it mic'd and hooked up to a computer to aid in smoothing it out and no matter what i did it would either create a gap, a big over lap with cancellation, or a massive peak, or a dip depending how i had them crossed over.  At the time i was only able to use 12 db crossovers, , if i were able to use steeper crossovers it may have been slightly more possible, but if your a picky listener just throw the 12's in, power them properly and build a A+ box for them.2003 Chevy Avalanche,Eclipse CD7000,Morel Elate 5,Adire Extremis,Alpine PDX-4.150, 15" TC-3000, 2 Alpine PDX-1.1000, 470Amp HO Alt.