I beleive it can in some circumstances cause the turbo to overspeed and that can in turn do damage.

I run 25psi on my Stage 2 hybrid T3 and don't/won't use a DV. ERST's do not respond well to the addition of a DV. FRST's are better but as has been said so many times they serve bugger all purpose on most road applications.

I would honestly not bother but it's each persons choice. I'd rather spend the cash on something that enhances the performance though