I use pedders maroochydore for my falcon,very good at there work,have to agree with you about B.J.Tmart never again,Im due for new feet on the navara so I'll take it there. But i think it just depends from shop to shop if they have people like your mate that really know what there doing...
No mate,I got a set of 175 narva's and had the same problem your having, auto lecky said the relay's that come with kit are crap,replaced with a better 40 amp brand and no problems since.
you should be able to grab the tailshaft just above the bottom uni and try to move it side to side, up and down and you should feel some play that shouldn't be there.