I've been rotating through 4 different kinds of r-comps this season and wanted to share my thoughts and impressions on them in case some of you are interested. Here is what I've been running this year.
245/45/16 C71 Hankook:
I love this tire. I have gone through several sets the last couple of seasons. Great value, great performance. They feel like they have tons of grip. Decent life, I usually get 60-70 runs out of them with flipping. They seem to taper off pretty gradually as they go through their usable life cycle. They will fall off with co-drivers on hot days even with spraying. Great tire for single driver cars or co-driven cars on cool to warm days.
245/45/16 C51 Hankook
Just started using this tire this year and got a set at a nice discounted rate so decided to take a gamble. This is Hankooks medium compound tire that is commonly used in road racing more than AX. This tire has been quite a pleasant surprise. As I expected, once hot they perform quite well. On 90+ degree days with co-driver these things love the heat and the results indicate just as fast as C71's or faster in similar conditions. These tires do not require spraying and I would recommend against it because the hotter they get the better they seem to work. For hot weather, this tire is a good choice. Should see longer life than the C71's as well which is a bonus. If you've used V710's in the past and like them, you'll like these. Similar grip, long wear and they handle heat as well or better than the 710's.
225/50/16 Hoosier A6
Gold standard for autocross and the benchmark. I've always liked the Hoosiers, but given their price premium kind of expect more. Results indicate they aren't much if any faster than the other less expensive options out there. They don't feel like they have more grip than the others and some times it feels like less, they do however have better feel in slaloms and quick transitions compared to the others. Life is short, maybe 40ish runs typically out of a set and they fall off fast when they do go. They don't tolerate getting hot very well, so you're probably going to run into heat management issues on hot days especially with two drivers.
245/45/16 BFG R1-S
Just tried these tires last month at the Pro/Tour in Blytheville. First off you need to run huge pressure in the fronts compared to the other tires. I ran the usual pressure initially and it messed up the shoulder of the tire with some metal cordage showing after only 12 runs. Sidewall feels soft compared to others and these tires do not tolerate shoulder wear well like the others. It seems you need to drive on the top of the tire literally. My findings are they need 7 psi more than the other tires which puts me at 52 psi front. If you try these tires, start 10 psi higher than usual and pay close attention to the wear triangles on the sidewall. Do not allow tires to wear below the triangles or you will run into issues. Initial impressions to me, they feel very similar to the C71 Kook. More testing needed, but I'm not crazy about having to run that much pressure and they seem to have durability issues.
Here is a pic of the R1-S after 12 runs and 45 psi in the tire. As you can see they were rolling over a bit too much and require more pressure. Sidewall now f'ed on this tire.