Mine sounds the same, I should have checked the rpm's at idle when i had it out yesterday, but its the same way. Quite a good amount of rattling and knocking at idle, but goes away once throttle is applied. It rattles so much that the water in the footwells vibrates bounces around. Very similar to the old skis as you mentioned.I'm trying to figure out what "normal" operation is for my new Spark in regards to some rattling/knocking in the driveline. At idle (around 1400rpm) in the water, there is a knocking/rattling sound coming from the driveline. No vibration. It reminds me of what my 96 XP used to sound like. Once you give it some throttle and get over 1800 rpm, the noise goes away.
What does everyone else's Sparks sound like at idle?