ACE Auto Rental & Renting a cellphone in NZ

Hi There,

I'm going to be spending two and a half weeks in NZ next month (making
my way from Christchurch to Auckland via the scenic route...) and I'm
trying to book a rental car. I've found some OK deals from Budget and
the other majors (Avis, Hertz, etc.), but the best deal that I've
found by far is from ACE Auto Rental. Does anyone have any experience
with them, or any tips in general?

Also, I was going to rent a mobile phone while I was there to call
ahead to the next town and such (and receive incoming calls from home
in the case of an emergency). Any tips on prepaid cellular operators
where I can get a reasonably priced prepaid mobile?

Thanks in advance! If you want to email me privately, just remove teh
DONTSPAM from my address.

-Chris