I might be new HERE, but these endless tire discussions run rampant on every forum. I'll make a couple of points and the op can make his decision, but first...
Lets get real people...
These oem tires (the R rated Advans) are a complete waste. NO, they weren't put on the car(s) because it was the only tire. These, JUST LIKE the Cup2's and Trofeo R's are designed so manufactures can run certain lap-times, around certain tracks and brag that they did it on a street legal/dot tire that can be purchased with the car. Its also why they are WAY over priced. Its a very specific niche. That's it...nothing more, nothing less. Its a street legal dot R...Bam, done! (for the most part, you get it, I hope)
Moving on. You've essentially got two options. R888R's or a few different nearly-as-good extreme street tires. My current favorites are the RE series. I had both RE11's and RE71R's and they are as good or better than R888's, 8 out of 10 laps. This is a FACT! Not opinion. FACT! R888R's however are a new block tech with stiffer sidewalls and give warnings MUCH earlier than its predecessor and also don't fall off nearly as quick. They are really good.
So which to get? You have the cup wheels so you're in the acceptable range of a 205/45/16 and 245/40/17 in the RE71R's...Get those and don't look back. If you aren't tracking it, getting the 8R's to temp might be a problem. Canyon carving and still having double the tread life + better wet is reason enough to stick to those. I know plenty of people who run 888R's all the time, and its fine, but the margin on the track is so close between these two in HPDE events, that on the street, it should be easy to see why the 71R is the better choice. I don't think people realize how sticky these 71Rs get, they are an incredible tire.
Just run slightly lower psi levels and you're golden.
2007 Lotus Exige S - Aspen White