I ran K&N's in the stock ears for a few months. It ran fine for quite some time, but started having an issue with running rough and dying at low speeds/idle. Had to keep revved to keep it going. Nothing to do with K&N's in the stock ears, just coincidence.
Following the sage advice of several members here, I dove in to the carb rebuild. I disassembled, cleaned and installed the 142/42 jets with the two shims on needles. After reading about the added responsiveness AND seeing some before/after pix, I opted for the ear shave with K&N pods at the same time since I had to take all that off anyway to get to the carbs.
I also coastered with some homemade plates. Have not regretted it at all. I do think it looks better than stock, and I know it seems much more responsive.
Malibu Shades windscreen, headlight visor, custom dashboard with voltmeter and clock, luggage rack, extended backrest, Viking saddlebags and toolbag, Wingerline engine guard with foot pads, light bar with halogen bulbs, Hardley Sportster muffs with crossover, homemade coasters, earshave with K&N pods, 142/42 jets with 2 shims each needle, MCCT's, AGM battery, coil relay mod, Iridiums with yellow NGK plug wires, relocated R/R, WOLO air horn, VN750.com chrome radiator guard