I ended up getting a set of RE71RS in 295/35/18 as well. I ran them last weekend and my overall result was similar despite the REs being less than optimal when brand new. I did get the Tire Rack heat treatment which helps a lot. It makes them much faster at the first event and more consistent during their lifetime.
I would speculate the P1s are faster if you can get them up to temps and so far I think the power down and braking are likely their largest advantage. An extra 50mm of tire probably helps there, lol. There's probably less difference in cornering grip.
Anyhow, here's results from SCCA event #2 at CO Air and Space Port. I was P2 until the last run of the last heat by a new driver in an '18 GS Civic Si sent me back to P3. Nobody was all that close to the winner, but even so I'm super happy to win over Darden, who beat me last weekend by less than .1s.
So far I'd choose the REs as my only set of autox tires as the P1s take too much heat for some events. However, I am extremely happy with the P1s on track and there's no way I'd go back to SC3s. It'll also be great to have the option to use P1s on hot days or if I have a codriver, so I think they will get plenty of autox use. I can see needing a 2nd set this season as I'm trying to get more track days in.
