Raising the rev limit on stock ECU

[Ivan141]

Much has been discussed about this specific topic before.. there is nothing magic about messing with the crystal oscillators that the CPU clock works with. It's basically making the ECU timing and calculations inaccurate with the side effect of it reading a lower value for RPM.
No data about which crystals to use is known to me, though I would expect you need to make the clock slightly faster (so it reads less pulses per time unit).
Possible other side effects this might introduce are at your own risk (you'll have to discover that for yourself I guess, I wouldnt know).