Thanks to a screw in the road (luckily at the entrance to my subdivision on my way home) I got a new set of tires from Tire Rack. Of course the Road Hazzard was 1 week out, so bad timing. I decided to bump up to 275/35R19s. From everything I read in here, it seems like a decent fit for stock rims without much variance in speedo accuracy or performance. So far, I really like them. I can notice a slight difference when pushing hard around steady-state corners but I think they fill out the wheel wells nice and have actually softened some of the impact I normally feel on a couple of local bridges in the area. I guess the added sidewall give a bit more cushion(?). I used GPS on my phone to verify the speedo has changed very minor (1mph @ 70). Overall, I would recommend that size for stock SRT6 wheels. Any wider and they may stick out a bit close to the wheel lip. Going with the 35 vs 30 series saved me $100 in price. I prefer to think of the savings rather than the cost!!