Rite where do i begin.

1. After reading some info on other forums and other bits and bobs im still unsure on the job of the 9th injector. does it need to be there and if it does whats the significance of its position in the fuel rail???
2. i understand that these rover V8's are not high revving engines especially as ours is i believe is standard but what should be a maximum rev figure??? our rev limiter in our bosch ECU is set at about 5K if this is low how would i go about changing it on the bosch system??
Would really appreciate any feedback to these questions so thanks in advance.
joe