XRAY - Model racing cars

Hi all,
I'm currently having some problems installing the engine mounts for the RPM/Speed Sensor of my DX3S radio.
It seems that there is not enough room for it between the brake disc and the fuel tank! In addition the engine mount that supports the sensor seems to be too long for my Sirio Evo4. Even the sloted holes available on the mounts doesn't seem right because some of the screws get covered and i'm only able to fix the engine with the 2 bottom screws!
Can someone advise me of similar problems and if there are any particular way to install this engine mounts?
Just another issue.. is it mandatory to install the decal on the flywheel?
Thanks in advance.

First of all I think you must be aware that Spectrum can not create things making it fit on all cars and Xray does not have to provide a solution, if it does not fit you have to be creative to mount it in another way.
Maybe it is wise to show a picture where it goes wrong?

The decal is needed because the sensor is using it to react on.