I know a few people may think I'm crazy, but there's a nice 2 and a half to 3 mile stretch of road I take to breakfast early Sunday mornings, you are coming down off a hill and can see for miles. I like to open it up once in awhile when the coast is clear on this road. I had the speedometer up to 180 mph this morning, the tac was at 5,800 RPM and the car was solid as a rock, still pulling hard when I let off. With the car having 285's on the back, I would have been running 186 mph. Renntech tuned my ECU for 93 octane, I run 94 octane and they raise my redline to 6,200 RPM so I do think an SRT6 will hit the 200 mph mark, I got this following statement from a tire size calculator. --- When speedometer reads 60 mph (96.6 km/h) actual speed will be 62 mph (99.8 km/h): 3.3% faster. When speedometer reads 60 mph (96.6 km/h) actual speed will be 62 mph (99.8 km/h): 3.3% faster.