Fixing bouncy floors...

I'm in the process of assessing how to fix my bouncy floors.  My house is not about to fall down, but Ryan Homes builds to code and this usually means floors will have more vibration, spring, bounce, deflection, acceleration, whatever you want to call it.  My words:  the floor moves when people walk and I would like to eliminate as much of the deflection as possible.  So now I need to figure out how to fix it.  Tom Silva from 'This Old House' suggested a method that adds a 2X4 flange to the underside of the floor joists.  Has anyone tried this?  Does it help?  I've also read about a product from Luxor Corp. out of Vancouver, BC called IBS 2000.  Essentially a type of retrofit cross bracing system that is designed to absorb a lot of the deflection and eliminate much of the acceleration and vibration in the floor.  Ironically Ryan Homes has used this product in the Capital District in the past.  Again, can anyone offer any opinion of this product?  It isn't too expensive, but I hate to throw money away.  I don't mind paying to fix my floors, but whatever method is used, it better work.  If you have any experience fixing bouncy floors, drop me a line.  Thanks.