LS1's due to their linear torque delivery don't feel as quick as they are compared to a BOSS. But rest assured their top end is vastly superior even in a 235kw tune. I think you will find that the car was quicker than it felt.
A bit of trivia for you guys. A VX 225kw tune runs 11 degrees of advance around its peak power mark. And a
AFR of 11:1. With a good tune most guys like myself are running about 24 degrees of timing and an
AFR in the mid 12's. This gives around 240rwkw's and better economy to boot. Kind of explains how detuned these things are from factory.