New intake and muffler

First off, i was thinking of putting a performance exhaust on the runner. Something like a flowmaster or magnaflow. Ive heard that performance mufflers dont sound that good on toyotas, is this true? Is it worth getting one?

Second, I am thinking of getting a new intake. With that big round filter... I have also heard bad news about these things to, is there any good brands out there, and is this also worth it? Will it affect performance that much?

If you want to get more power put headers on it. You didn't say what year or engine, but if headers are available they will give you a lot more power than a muffler or a intake pipe.
I don't think the stock muffler is particularly bad, but a genaric turbo muffler will give you as much gain as a flowmaster or a magnaflow without the noise.

The intake pipes are a crap shoot. Its hard to say if they add power or not. If they do add power we are talking 2hp at the most and I think $200 is to much to pay for those kinds of gains.

Well, I have seen cheap intakes on ebay for about $50. Should I trust these generic kinds? And by the way I have a 3.4 V6 97' Runner. And, around how many miles should the stock cat. con. and muffler be replaced?

The good intakes will have some kind of block-off from the rest of the engine compartment. You don't want to suck in hot air from the engine compartment. The stock Cat. Converter can last up to 200,000 miles although 100,000 is a more common replacement interval. A high flow cat would be a good idea too. Remember, their is always more power to be made on the exhaust side as opposed to the intake side.