Get rid of those awful awful tyres immediately. Before the ditch finders do as their name suggests. Or worse.
Either get some Bridgestone RE050s to match the front, or ideally replace the whole set. I'd suggest Falken FK 452.
Good advice
Have any of you experience of Maxxis Ma-Z1 tyres?
There is a "Drift" variant of the MA-Z1 which is not as good as a road tyre as the "standard" MA-Z1, unfortunately it was the Drift variant which autoexpress tested (and it rated it above some premium contenders):
So, they are not as good as the bridgstones, but they aren't ditch finders. I bought some replacement alloys for my Z that had "sunway" tyres on - these were truly dreadful and true ditchfinders causing the car the slide around in the wet - they didn't last long.
So I would suggest the OP gets their alignment checked (inc castor / camber) by a reputable motorsport place. Alignment is critical on a performance car like a Z.
I would check all the suspension bushings (bannana bar etc) as these so crack and cause alignment to shift.
Check the date code of tyres - I would replace after 7 years on a road car as they do "go off".
No, I have not tried the Maxxis Ma-Z1 and it would seem from your post you, wisely, chose to fit them all round.
Its the mix of two completely different tyre types that from the all the hundreds of tyre posts I have seen on here indicate is invairably the factor that can lead to sudden loss of grip. The structure/compounds/tread patterns vary from manufacturer to manufacturer and indeed within the same company. For instance it is it is well known that mixing Bridgestones 040's with 050's can be quite lethal.
And I have moved away from the 'preferred' tyre choice of Nissan by fitting Vredsteins Ultrac Sessantas - although listed as a premium tyre they seem largely untried as far as I am aware on the 370's although there has been good reports of them on 350's. So, I am being something of a guinea pig as I really felt the 050's could be improved upon when pushing on, especially when you want to steer the car with the throttle.