Buy Nissan @ your own risk!
The Nissan Altima, admittedly a nice looking car, is a piece of crap. I have a friend with a 2004 2.5 and it won't pass state inspection and the engine is about to blow. The car was manufactured with a defective catalytic converter that comes apart and gets sucked into the engine and causes engine damage. Nissan knew this yet still produce this lemon for at least 5 years. The part has just recently been changed. Apparently it only affects the 2.5, but considering the total "fuck you" attitude Nissan shows on this matter, I personally wouldn't buy shit from them.
If you own an Altima 2.5 and it's using alot if oil and water, you should prolly sell it while you can. Just a friendly psa!