Hey man, not looking to throw fire on you.
Neither of these wineries has a good reputation for producing consistent quality. Pirramimma is another Mclaren Vale inflated RRP character, always clearing cough through Grays, DM etc. Im not saying there isn't some good there, but you're gambling.
By contrast, Dave Powel is a great winemaker whose been on let's say an exceptionally rough journey since his exit from Torbreck. I'm looking forward to seeing him turn the corner, but I can't in good faith recommend him out for the moment.
Best advice for you would be Alex Head (>$20), Hardys HRB 2018 (~$20), GB Filesel 2019 (>$30) and Torbeck Steading (~$37.5). Reliable producers and blenders ensure quality each year.
Step up is Luke Lambert Syrah, Margan Fordwich Hill Shiraz or Timmo Mayer Syrah. All ~$50.
Remember wine is poison - so may as well drink the good stuff. Cheers!
EDIT: try some straight Mataro from Greenock creek or similar if you get the chance to.