Have you ever just added amps and processing to the OEM stuff though? I have. As have a large number of the SQ freaks on
DIYMA. Even those guys will tell you how amazed they were at what some clean power and more control can do.
The drivers are the weak spot in ANYONE's system. They introduce the most dostortion, are the toughest part of the install and are an all around PITA to change, tweak, adjust, whatever.
People drop in $500+ worth of component speakers and wonder why they aren't blown away. Think about it like this... what if you just added a Sundown/DC/DD whatever sub to the factory system? Would it be automatically awesome? No.
He isn't seeing 270w. I've done it myself. Took my factory system and just added a little 50x4. It floored me how good it was. I was convinced that "good drivers" wold take me to the next level. Well, a few hundred bucks and several hours of install later... I was wrong.
Look, I am not saying stick with the OEM stuff forever. I am just saying don't automatically swap them out assuming that it's going to magically transform our system. Get your foundation solid. Add some clean power and some slick processing and giev them a chance to shine. If after that, it's still not pleasing THEN start swapping drivers.