hey mate
i e mailed ppg direct a while back regarding a ppg dog box for my r32, i was told by them that the gearbox's need to be pulled down and inspected EVERY 12 months and at that point the 2nd and 3rd gear dog rings would need replacing and posibly 2nd and 3rd gear themselves, just the parts add up two about $1000.
then you have labour to pull the box in and out if you cant, so will add up.
he did say that you could just drive it till it played up if you wanted but they didn't recommend it.
hope it helps, if not look on www.ppgearbox.com and e mail them about the kit you want