I haven't owned (or driven for that matter) a FK8 but from what I read I would well imagine that they would be a very different beast to a GT-R - which I haven't owned personally but my Dad is on his third one and I have driven all of them a fair distance as well as tracked them.
While the GT-R is an incredible machine, and certainly not lacking in the cornering side of things, they can be quite difficult to tame once you have managed to reach its limits. But the reality is that you would never reach this on conventional roads unless you had a death wish as they really are very capable given their size and weight.
That being said, owing to their size, they aren't really a 'toy' as such as (especially around here) they are too big to use on a proper B road blast, where you need the whole road (and then some in some cases) to actually feel as though you "having fun" - so long as you don't look at the speedo!
You will need a de-cat Y-pipe without a doubt as they sound far too tame out of the factory (fitted with four catalytic converters - the Y-pipe removing two of them). And if you go for MY17 onward, the OEM system is titanium instead of stainless steel, so the cost of this Y-pipe is eye-watering - over £2,600 for the one currently fitted. Whereas the Milltek one he had on his first GT-R was around £500 (steel - but also a ghastly design with poor flow).
Then there's the cost of them that most either ignore or aren't aware of (and depending on the level of care you give it).
The average cost of ownership has reduced of late due to him having not been back in the UK since Christmas, but there was a time where the average yearly cost, without fuel, was setting him back £17k per year in servicing, insurance, sundries, etc. And when he does visit, he'll happily spend over £1,200 on fuel in two weeks.
They are an amazing drive though. Yet also be mindful that they really shine in the upper regions of third and fourth gear - so 110mph upwards. Most people are too scared / unwilling to drive at these speeds, which makes ownership of such a machine pointless in my eyes as you aren't utilising its full potential.