I have heard of quite a few of the balanced pipes getting stress cracks, even when nearly new. Also apparently not easy to fit, so possibly the best option may be to go for exhausts without the balance pipe, unless you really are after a standard look.
A friend of mine here in the UK has had problems locating some balanced pipes as the usual main suppliers don't have any in stock, and of the two he has located, one didn't fit (line up) and the other stress cracked shortly after running the bike. He is now awaiting his third set!
I personally would not bother with them.