[Funny]

- I have always used Bosch O2 sensors, that's why I recommend them - never had one fail.

- Yes replace both at the same time, make sure you get penetrating oil at the same time and hose the front one. It's located behind the engine on the exhaust manifold, it's a pain to get to unless you are a contortionist, so you only want to have to replace it once.

- If it's throwing a code, what code? If you don't have a Scangauge, get one - it will pay for itself within a couple of months on the gas you save using it.

Common codes:
P0420 - catalytic converter efficiency low bank 2 - replace O2 sensors (at least the rear one)
P0446 - vapor canister issue - tighten gas cap and hope that the evaporator canister's valves aren't sticking. About a $200-$250 part.

-I think that your engine isn't a 1ZZFE, therefore I don't know all there is to know about it. But your oil capacity should be about 4 quarts.

-I wouldn't change transmission oil to 5w30 only because of the age and mileage of the vehicle, but it's safe to assume that changing the oil with the stock viscosity should be okay. A side note - this is a pain in the ass for most Toyotas because of the angle that you have to be at to get the MTG oil back into the tranny. Just a warning - have extra on hand.

-As far as horses go, I wager on them in Saratoga NY every year. I know they like apples and carrots, and that the bump in the bottom center of their hoof is called a frog. Keep the hoofs trimmed or the horse could get Laminitis, a debilitating problem that usually means the horse gets put down.

Sorry for being such a know it all, I just don't want you making the same mistakes that I have. Check out the PM I sent you Dave for more info.

-Funny OUT.