$4700 to replace the cat converter? Please dont buy from them their extremely high priced and way out of line!
Whats the mileage on the truck? Cat converters and other pollution control parts are warrantied differently than the rest of the truck.
If the mileage is to high then look at Summit and some of the other aftermarket parts manufacturers, then strike a deal with a local exhaust shop to have the new cat converter welded or bolted in as the case may be. Might check the exhaust shops first, sometimes they have decent resources for replacement parts that are much cheaper than factory.
The price you were quoted is way to high, this job could be done for less than $1000, possibly in the $500 range depending on the best deal you find on a converter.
I included a few samples of Converters I found in a search on Google using "Catalytic Converter 2005 Tacoma" do a search for the best price/quality these are parts houses I've used in the past so I trust them, also I dont know whether your truck is a 6 cyl or 4 cyl, that might change the price slightly but not more than a few dollars.
http://www.discountcatalyticconvert...D(part:Catalytic+Converter)&events=partfinder
http://www.discountcatalyticconvert...D(part:Catalytic+Converter)&events=partfinder
http://www.discountcatalyticconvert...D(part:Catalytic+Converter)&events=partfinder