Fl22 coolant

I read that the Mazda coolant lasts 11 years.

I am a new owner of a 2006 car so want to change the coolant. If I use the genuine stuff from the dealer does it need diluting with deionised water or is it used neat? I see I need 7.5 litres!

Any idea what dealer charges? Is there a branded alternative? 

Ta

D

Buy it from mx5 parts 12 pound 5 litres ready to pour in. Only avaliable in 5 litres