Hi Dave
Thanks for the comments, and sorry for not replying to this post. I got your email and then promptly deleted it
To answer your questions, I did use the factory MAF. Originaaly I was having trouble with it because the brains at Mazda had the ground for the sensor routed in with the air bag harness. When i removed the air bag wiring, I lost the ground. It was pure luck that I was loooking at the wiring diagram for the air bags that i spotted the common ground.
I can take some pics of the MAF and post them later.
I haven't had any issues with cooling yet, but I still haven't put that many miles on the car, and it hasn't had to sit in traffic (it is so low I would be more concerned about asphixiation than cooling if I was stuck in traffic). I do plan to add shrouds and a grill, but i have not got round to it.
Feel free to email if you have any other questions - I am more than happy to help whever I can.
Adam