Cheers guys. I have specified to my tuner that i want new belts and a new ARP bolt and washer put on. From researching i have that the only you generally run into is when people try and reuse the old bolt. The cost of a new bolt verses possible repair costs it just aint worth risking it on the old bolt.
That's good but as I said at the beginning sometimes the balancer is a tight fit and people use the balancer bolt (whether new or old doesn't matter) to pull it on.
And that's where problems can arise because sometimes the bolt only catches 1 or maybe 2 threads and as they put pressure on the balancer the bolt strips out the internal thread.
Then you have to be really careful not to cross thread the new bolt in the crank.
BTW I have never had any problems running the 25% U/D Balancer despite what the gloom sayers say about them and my car has power everything.