Ah, no way less than that.. unless you take your car to a shop where they absolutely ream you with the price of the swap.
The B20Z2 runs around $1,000. If you do the work yourself, you don't even need a lift to do it!! An elaborate set-up of jacking up the front end to make room to remove the stock engine from underneath and then to replace it with the new motor is all you need to do. It will cost you.. well the engine, plus a few gaskets and other odds and ends, and of course a good chuck of time, but nowhere near the 4 to 5 thousand mark.