I've been building and driving 4g63/64 powered vehicles since the mid 90's and I've never had a balance shaft belt fail, but then again I properly maintain my engines. I still build high HP evos and 4g63 based things and leave the counter balance system in them with no failures to date. I used to take them out but figured out quick that the power gain is negligible to none, the resonant harmonics introduced are annoying and will fatigue and break various hard parts in and bolted to the engine faster, it's work to remove them and anyway your running a chain in the G45b so you don't ever really have to worry about it breaking.
But hey, whatever tickles your pickle <img src="/forums/images/graemlins/notooth.gif" alt="" />