The carbon build up still seems to be an issue, although hasnt been seen on mine (yet?). Speaking to a few tuners, the HPFP is an issue if you follow BMWs suggested oil change intervals. Which is something like 10-15k miles. Myself and other people I have heard of that change their oil every 3-5k havent seen any issues with the fuel pump. JB4 is hugely popular, but youre much better off getting a custom dyno tune (you will probably need to provide your own Cobb access port btw). The JB4 tunes can literally disappear due to the very complicated data bus setup on the BMWs.
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