Initially, I was happy to note that my 1kyuu grammar book had a lot less grammar points than level 2, so I thought it might be a little easier to study for. However, as I am taking the practice tests, many of the answer choices are level 2 grammar as well. I have done ok so far, but I will have to go back and review level 2 grammar. Which is fine, there's a lot of 2kyuu grammar that I hear but never use. When I hear it, I think, "Ah, level 2 grammar that I completely forgot about." Then I get sad. Then I go study, and am happy again.
There are benefits to taking these tests, outside of trying to get into Japanese universities. Some complain that it's all archaic or written grammar, but that isn't completely true. For example, in Japanese department stores, I often heard something like ｢お客様、8時をもって終売致します。」 and I wondered 「なぜ誰かが「時間」を持ってるだろう？」 That's an example of (level 1) polite speech you may never use, but is useful to know (をもって=で).
That's the trick to Japanese. A foreigner can come to Japan, find a job, and live a long, happy life never using keigo. But if you don't understand it, you will not know what is being said at convenience stores or restaurants or well, most everywhere. Not that you are screwed; you will get the onigiri you want at the 7-11, but it's worth learning keigo and teineigo. Unless you enjoy making everyone speak to you in English, which I find to be unacceptably revolting.