IAX2 Trunking load balancing router

My internet is slow
I can have 2 isp, each which can give me 128 k bandwidth
one is dsl and one is wireless

I am using iax2 trunking between 2 asterisk

if I use a load balancing router such as zywal 35 would quality be screwed up or should it work normal?

I prefer to use 1 trunk instead of 2 , this reduces the overhead a whole lot