While there's nothing wrong with the 53-39 and the 12-23 cassette, let alone suicidal, it's almost pointless. Unless you face some specific circumstances where you need the 53x12. Speaking personally, I'm not any faster in my 53x11 gear than I am in 53x15. Maybe if you're a brute or do a lot of drafting at around 30mph but otherwise it's way down the priority list.