I don't think the Altima is a low clearance car, unless you lowered it. I think they mean cars that are very low to the ground can't handle it because it will hit against the driving surface, and probably cause an oil leak.
That looks like a handy little product, I like the idea of being able to drain the oil while its still hot and all. Probably much less of a mess, too.
I don't think I would trust it though, that thing springs a leak and you can kiss the engine bye bye. I read how they have sold over 2 million on their website and no reported problems... words are cheap and I'm still skeptical.
I have had them on a couple of cars and I have been very pleased with the product. I plan on getting one for my Altima. I wouldn't get the extended one for the Altima, the regular one would do the job just fine.
Is it just me, or does it look like the oil drains onto the crossmember? I haven't done my own first change yet, but the dealer did the first one, and there's residue all over the crossmember. If so, then it seems like the one that allows you to attach a hose would be neater. Being that there is a crossmember in the way, it would seem pretty safe.
The oil from the pan shoots straight out of the back of the pan so it dosen't get on the crosmember. The filter is directly over the crossmember so when you remove the filter the crossmember gets covered with oil.
I would pass on the extended version not because it will be too low, but because it dosen't ad anything.