swap factory with aftermarket amp

So after many problems to install my Alpine Double din into my IS250; I have decided to just power my stock speakers with a aftermarket amp and power the amp with my DD. But the problem is, is that the 2006 IS250 has 13 speakers. How would I go about wiring them to my 4ch amp? I heard some people say that they dont wire the tweeters but I was wondering how would the best way to wire it? Here is a wire diagram I was thinking of for the most part to wire the main speakers like this It seems like some speakers are wired to the same pin, on the diagram. But can some one with more knowledge help me out? Thanks

anyone know?

i would first test the impedance of the stock speakers leaving the factory amp, write them down, check you aftermarket amp and see if its 2ohm stable in stereo(it should) I wouldnt mess with the center or factory sub, if your using the factory deck i would check into using a LOC,Go BIG or go Home                                    it might not be broke, but lets fix it anyway

did you by chance purchase a toyota/lexus amp integration harness for your initial install? I use them all the time and all speakers work everytime. the metra part number is TYTO-01