2016 SL, 22000 miles and I just replaced all 3 tires.
This is my 4th rear tire (I don't worry too much about rated tread life, I know it will be short no matter what) and it's my first time replacing the Kenda front tires.
I went with Nitto NT555 G2 all around. Maxed out the sizes for stock SL rims: 245/45 x 18 at the front and 275/35 x 20 at the rear.
I also bought a second rear since I know it won't last nearly as long as the fronts and I got a bit of a discount for 4 tires instead of 3.
The Nitto are a bit cheaper than the alternatives I was considering. I had a BF Goodrich Comp2 A/S at the rear before this but realized I don't need to compromise with an All Season tire. I'm looking for mostly dry and occasionally wet traction.
From what I've read, All-Season Ultra High Performance tires (like the Comp2 A/S) may compromise some dry and wet grip to gain winter traction. Summer Ultra High Performance tires (like the Nitto) are generally better in the dry and wet, though they are not intended for cold weather and won’t grip in snowy or icy conditions. Well I don't plan to ever drive this thing in the snow and ice.
The Nitto does seem to have more grip although I haven't tried it in the rain yet. In any case I avoid the rain whenever possible and know to slow down when I get caught in it, so I think these will work well for me.