Need help for strange Vems laptop connection issue ????

[rossi46numberone]

Good news,
Checked my Master cable ground and it was going to break on the junction point with all the grounds wires from the ecu .
I repair it and then withdraw it from the head cyl and plug it on the battery.
I also put the common signal ground of the smart coils(triggrer side)on the head but far from the power ground coils.
After that I've made a test on the road for about 50 km with my laptop connected with external power supply on the cigaret connector.
Under different boost,rpm,load I never lost the connection and Vemstune never freezed like I had before.
Now just one issue subsist,how can I kill the speaker noise??
I was thinking it probably come from the N75 boost control valve because that i's seems to be in relation with the boost.....
Should I have to put a flyback diode like the injectors regarding the fact is it coil to?Perhaps a CAP??
Or the solution is anywhere else??

anyone??