Buy the SDS first and then the ring. Both are outstanding upgrades and worth having. As to cost, well, in my opinion, none of the audiophile crap warrants the prices charged but, if you want to play you have to pay.
VPI periphery record ring for VPI Scoutmaster
How much of an improvement does the VPI steel periphery record ring make? Do you think it's worth the $500 US retail price? Or would it be advisable to first look for the SDS, then afterwards purchase the ring? I'll be using it on a Scoutmaster turntable.