The stock for this is 5-5-5-15 @ DDR2-1066 with 2.2v. Crucial Ballistix DDR2-800 is specified to do 4-4-4-12 @ DDR2-800 with 2.2v. All Crucial Ballistix has either Micron D9GMH, D9GKX or D9GCT ICs, so any Ballistix should be fine at the same speed an voltages specified for any other Ballistix...
You might give a try to clockgen, but their official site isn't up at the moment, so you'd have to google for a download. I don't know if your motherboard or chipset will be supported, but it is worth a try.
For specific results for multiple types of usage, check out this article.
As far as gaming goes, the difference is negligible. File compression and encryption gets some boost from the tighter timings. It makes a bit of difference when multitasking intensive apps. The test on the site were...