According to some of the commentators the Viper's V10 made enough mid range torque (which is what counts when going 10/10) to not make this a worry. However, I now have some claims from R&T to disprove this. During their Viper vs SLS comparo, writer Peter Egan said this;
"Despite its massive its massive 600 lb-ft torque rating, the V-10 has to be worked harder than you'd expect to run with the lazy-fast Mercedes. Some of this may just be very tall gears in the manual 'box, but some is no doubt from the relatively high rpm torque peak"
This is even more embarrassing when you realize the Merc only has 479 lb-ft, which is made around the same RPM as the Vipers 600 lb-ft. Now some of this is down to the gearing (the merc does have a little bit shorter gearing), but when you have a 120 lb-ft advantage excuses like these aren't needed.