I have a Draxas header, f2 flex and nothing but a resonator the rest of the way. I LOVE the sound. The drone isn't that bad (if you ask me). The header and flex are 2 1/2 and the MBRP exhaust is 2 1/4. It took a little to get used to the sound, but now I can hardly hear it. Everyone always tells me how loud it is, but it's normal to me.
2006 Focus ZX3 SAP, Draxas Header, FS Werks Flex pipe, MBRP exhaust, CAI, Tuned, Debaged, tinted windows, FRPP lowering kit, SVT 5-spoke wheels, Black Halo Projector Headlights, Niteshaded Side markers and tails, Mazda rear wiper, mustang antenna.