Oh crap. My eyes are bad. I didn't even seen that extra brake caliper until today.

It's probably a parking brake mechanism. The size of the caliper shouldn't affect overall braking performance. That's the first time I've ever seen something like that.

 

I'd rather have the srt10 pickup and turn it into a sleeper if I had the $, but a viper is a viper, I'm just glad it's lasted as long as it has