I am with Shannons (have been for some time now). They said any mods, any power as long as it is engineer/rego approved (which I am). The the shell of my car is one of the only original parts left on my car. I have gone from about 17rwkw to 170rwkw and they have no problem with that, and I will move to more power in the future which will be no problem either.
Celica John, is it the mods and your age that's a problem? or just the mods (which we can only assume are not RTA approved???)
Mine is comprehensively insured for $430/year and I have salvage rights too (with no cost at time of claim).
I know age is a big problem with car insurance, I am now moving into the cheaper zone, one good thing about getting older I guess.