I have the Akrapovic slip-ons on my 1299. Not blowing my own trumpet here but they sound amazing, a lovely bang (and a flash of flame) when shifting gears, so much lighter than stock and to say they are very well made is an understatement. Keep an eye out on a popular auction site as I did for a pair. I paid £1300 GBP for a pair of used ones, which were after a clean looking like new