@tobys
The testers manual is at times vague with plenty of grey areas.
Does the tester know the difference between the noise level of standard and aftermarket system?
As suggested, fit a valve controller as I have and all is good.
You could always appeal a testers decision, that would put the wind up ’em.
FPM 375. MSD 350/380/400
DSC
Tractive Suspension
