I would disagree with DSJR n the mat. But from most of his recommendations he must have quite different ears from me.
Cable dressing is just fixing the arm cable so that it has little effect on the suspension.
Not sure if much will help with the warps tbh. The clamp will help if it is warped in a bell shape perhaps.
Invest in summat to clean yer vinyl as well.
Stick with the M75 for now.
Try Brasso for polishing the arm.