Got a bit of a conclusion at the end should you want to skip my stupidness
First, why all the VL bashing? Its the only decent Commodore anyway (RB30E ). Besides, the term sh tbox should never be used. Sure, a Excel might not be a nice car, but if your on a clay pan in the middle of nowhere... who cares?
In my experiences with insurance, a change of car in the eyes of the insurer is much more minor than a change of driver. Your idea of having your mother insured for the Skyline and you for the Mondeo could work, but I don't think you would save a significant amount of money (I'm too lazy to look it up so I might be wrong :laughing-smiley-014: )
Now for my long winded story.
Got my red Ps in 2004 (no V8, turbo or performance restrictions, as far as I read the rules) and I got it in an '88 R31 Skyline GX Wagon. Drove it to and from school and probably nearly killed myself a couple of times while doing it, but I learned how to control a rear wheel drive car. Anyways, year after and its time to pay for insurance. No record good or bad, still 17 and I could only insure it with NRMA for around $1500, third party property. (car was previously written off by my dad, we kept the car and re-registered it, somehow most insurers don't like this...) Needless to say both my parents and I where fairly shocked at this, so we decided to insure it under dad's name with me as the yongest driver. Another year passes, same thing happens again but come this around when we phone NRMA they said I was not on the policy. Then to have it properly insured under my dad's and my name would save me a whopping $200 from the original $1500, big deal . Thus, will not insure with them again. "Thankfully" the car did not pass rego due to some rust on the A pillar... To this day the car sits on the front lawn...
Then I got myself a V6 Magna, drove it for 2 months before my brother needed a car and I decided that it was too much of a luxury car, and I liked the "go-kart" feel of the R31. I bought myself a '91 Subaru Liberty GX, front wheel drive and almost all electric options. Insurance is easy, but it burns just as much fuel as my R31. Now I have enough cash for a tidy R33 GTS-t Series 2, but lack the balls to part with my money.
Anyways, before I write an epic novel here I would just like to recommend a car should you not get you Skyline would be a Gen 3 Subaru Liberty (2002 - 2003). (IMO) Looks good, goes well and hole their value reletivly well untill you sell it for your Skyline. Or if you still want an import a Mitsubishi FTO, although, insurance isn't going to be much cheaper than the Skyline...
Whatever you get just keep in mind that they all cars can break the speed limit, some just do it quicker than others
Conclusion: Skyline insurance should be full comp, unless you earn roughly $20k a week or you get a really dodgey one and keep an open mind, look around for other cars that aren't "sh tboxes" (beauty is in the eye of the beholder and all that stuff...)