Sorry the picture isn't so hot.
One thing is for sure about GM products, they rattle. Anyone who has a Camaro knows this all to well. Those of us with T-top equipped models have to put up with more than the usual noise due to the extra parts and the missing roof. A T-top car has no additional bracing beyond the T-bar to help deter body flexing. Every driveway approach becomes an exercise in flexing. The solution is a set of subframe connectors. They reduce many rattles and body flex.
These connectors are basically heavy duty bars that tie the front and rear frames of the car together and act as a truss to prevent body flex. I opted for Alston bolt-on units figuring it would be an easy install. It basically was. Alston manufactures the Granitelli units sold for the fourth generation cars as well. Here are some tips not emphasized in the instructions. The fuel filter bracket at the rear of the car may interfere with the left rear connection point and need to be moved somewhat in order to get the connector flush. The fuel lines may also need some pushing. Make sure the car is on flat ground and that it is put on jack stands such that the body is not flexed out from normal. Use a floor jack to hold each connector under the car during installation. The floor pan may need some massaging after installation to prevent it from touching/scraping on the connectors. There is a good chance that the catalytic converter will hit the right connector while driving over bumps. After driving the car for a short time, crawl back under and really tighten up the bolts to get the best possible effect. Having the connectors welded afterwards makes again as much improvement.
The Alston Group, 248 Depot Street, Antioch, Illinois 60002 (708) 395-3500 F:(708) 395-3550