QUOTE=Brazilbro;45183]Doesnt adding D.I. make it harder to upgrade your fuel system? Isnt that the problem they are having with the BMW I-135 running out of fuel past 6k[/QUOTE]
Yes, it makes regulating fuel much more difficult. Custom intake manifolds can solve this, but you're looking at a completely new control system/ecu for the car. Horse Power Freaks are known to do this and are working on a package for the 335i currently.
The n54 isn't necessarily running out of fuel past any rpm range, you're probably thinking of turbo efficiency. So far the n54 is limited to around 440rwhp in it's current set up (stock turbos). Time will tell if they can push that limit with the stock turbos/fuel system. One company has ported the stock turbos and achieved 500rwhp+ on the stock system, but I think that's pushing it a bit.
In reality, turbo upgrades are right around the corner with all the new flashes available. Hope this helps! :]
Additionally, a SC'd or Turbo'd VQ with DI -
