Secondary Air System- some have it some don't

I am looking at a 2001 DII for purchase. I notice it has no secondary air system on the engine. My 2000DII does.

Why doesn't the 2001 have it? Is it one of those emission things you have to have in California but not in other states? (I am in Alaska)

Is it a good thing that the 2001 DII does not have it?

Will I get better mileage w/o secondary air.

It does seem more powerful (peppy) than my 2000 but that's probably because my 2000 has 140,000 miles on it.

I would love to know the answers to some of these questions before I buy it.

While I don't know exactly why some have it and some don't, it is strictly an emissions system. If you look at the description of the system in RAVE it states, "When the engine is started, the engine control module checks the engine coolant temperature and if it is below 55
C, the ECM grounds the electrical connection to the coil of the secondary air injection (SAI) pump relay." It basically, and someone correct me if I am wrong, recycles the air through the injectors while the engine is still cold. I think on my 2000 the SAI runs for about 90 seconds or so the first time I start it up in the day. That was when it was working. :) I haven't had any problems with it not working other than the Service Engine Soon light.

Hope it helps a little.