The Rods are the same length from Sirio & Trinity.. But, rod length Does not determine your Stroke.. The Crank determines your Stroke..

The answer to your question, how ever, is it will change port timing.. Which could be good or bad, depending on which way it changes, and depending on your driving style.. I'm not a tuner, so I don't know which way will do what. One, thing I do know for sure if you only change the crank to a shorter stroked crank, you will loose some compression, same would be true if using a shorter rod.