First of all I can garuntee you that you see more 281s and LS1s on the street than you do viper v-10 motors.
Whats the deal with it being full interior or not? Or wether it has a/c? What does that have to do with ANYTHING at all? A/C is an option, you don't have to have a/c and every car on the road does not have a/c. Even if it does have a/c you think thats gonna take 1 second off the 1/4 time?
You talk about full interior whats the big damn deal? 100 lbs= 1/10th. You figure 1 seat probably weights about 30 lbs depending on if its manual or electric, carpet probably weights 10 lbs or less, the back seats which is just foam and leather. If you gut the interior and take out the a/c your talking maybe 2/10ths. You are starting to get petty here, lets stick to the engines, please. I'm not doubting the ability of a 281, but numbers are numbers, and the fact of the matter is 350 (technically 346) CI is alot more than 281, thus being the reason why the ls1 is the better motor. So this all goes back to my orginial statement: There is no replacement for displacement.