XRAY - Model racing cars

Hi All, <<corrected by moderator on request of Mister-E to invite others to join in>>

I've just bought and tried the new roll center alu holder (#303093) on my T1 Factory kit.
What's should be the result on the car's handling when this option part is used? I experience it as if the car has less rear traction.

I think:
- Upper rear arm length is shorter -> Roll center is higher.
Less body roll resulting in => Less rear traction.

Is this correct? I was running the car at AMCA in Apeldoorn.

How can I improve the rear traction then?

Thanks in advance.

Edward

Here is a picture ot the mod I have done to the rear mount. A common mod that allows you to switch sides when you are using short arms.