I'm surprised your missus is allowing to do what your thinking of doing.
I can see it now: For the 1st 12 months you will be over the moon, and then you will realise the repayments to the bank, the insurance, running costs etc, are eating up your hard earned money.
You persevere for another 6-12 months before coming to the realisation that you need to sell. Then another depressing period of time will pass when the reality of not being able to sell occurs. Have a look at how many R35s are on carsales, that only have 10-20K on them.
Its a big jump from a G6E Turbo to the R35 in cost. There are many other cars that are exciting to drive, that turns heads, and at significantly less cost,
How about a nicely modified R34 GTR for 60K? Or even another 370z with a TT kit for 70-80K? Or wait till you turn 30, when the 2011 GTR will be around 110K, and you will of had another 2 years of growth in your property and further savings in the bank.