What spark plugs should I use?? need help!

Hi
I drive '02 focus with spi and automatic tranny.
I wanted to check and if needed to replace spark plugs.
and look what I found:

there're 2 different spark plugs in my engine:
in first and third cylinder there is Motorcraft platinum AGSF 34 E
in second and fourth there is Motorcraft platinum AGSF 34 EG

Is it wrong or is it ok that i've got two kinds of spark plugs?
It doesn't look goog for me.

The second suprise is that theese spark plugs are not for focus 2.0l spi
I've found on www.motorcraft.com that for this model/year/engine are different plugs like:
AGSF 34 FM
AGSF 34 FMF4
AGSF 34 EE
AGSF 34 EEM
44 EE

What shoud I do with it? My old spark plugs are not in good condition and this is very strange because the car got 12000 miles and I'm the second owner so I think platinum spark plugs should be for around 100000 miles.

Which spark plugs should I buy: Motorcraft or Autolite or NGK or Denso?
Should I buy standard or platinum or double platinum or iridium spark plugs?
Should I use 4 spark plugs the same for each cylinder or two for two and other type for another couple of cylinders?
Arek
[email protected]
p.s. I'm polish so excuse me my language

I would definitely stick with the same plugs for each cylinder...you don't want any weird problems arising from that down the road. Right now, I have Autolite Double Platinum's in my car, and they're fine. Nothing exciting, just spark plugs. The NGK's are probably the best on that list, IMO, but also the priciest...I would probably go with the Autolites, or the NGK's if you have some money to spare.