thats what I was thinking. I have read posts of people getting 13.8 with intake and header on there r's. If I supercharged the gsr and couldnt get that, I'd be pissed. But yeah I too think the charger would give better usable power. I hardly get on it, I daily shift at 3-4, hardly go past 50mph. she's abaied, probably why after 165,000 miles on the gsr she still runs at perfect compression.