It's really a matter of opinion, most people shy away form them due to the points noted by luseboy. While others have great success. The fact of the matter is that it's your money, spend how you like but my opinion is run what you got. Do more searching in the FAQ section there are some good reading on head selection and prep work.
As far as the stock usdm manifold, it's square port so you will have to resolve that issue. But they flow quite well and the quench area is good. Just be careful on valve size they changed sizes during the p79 life.