Oh dear, I didn't include the last part of your post because it wasn't really relevant, apologies if you think it was.
The settings 1-9 in your case, will probably affect the fuelling and not the engine revs. The throttle position affects the revs. The road speed, mph, is directly related to the engine revs in any particular gear so is not a variable that will be affected by the tuning box.
What you can reasonably expect is that you would use less throttle for a given speed or to put it another way, your engine would produce more power for a given engine speed.
As a simple rule of thumb, the higher the number, the more power, now assuming that you drive your van in the same way, you should find that it will pull better, particularly up hills or on long motorway inclines and you should get better fuel consumption, probably in the region of 10% - 20% as a result of using less throttle for a given rpm.
You may find that the higher number settings will produce black smoke, (over fuelling), especially when you put your foot down, if this is the case then go to a lower setting until the black smoke disappears. On the other hand, if the engine management light comes on, this would also indicate an incorrect setting.
The cables that disappear, (there are usually 2), go to the common rail, where the standard cable normally plugs into the end of the common rail, the tuning box simply fits in between the standard cable and the common rail.
Any queries, speak to the supplier, in your case, Tunit, who are really helpful.
Once again, apologies if I upset you, but so far, between us, we have managed to hijack the OP's thread, so apologies there as well.
