How much a full blown build can cost it is definitely something to consider, which I had that option but from what I have read so far I think it is only for the 07's and up but could be wrong about that.
To me it sounds like a good deal, you get a good bang for the bucks. A JIMS 131 is cool if you like HP. Pros you get better cases, more power, good lowerend, cost is about the same or less than a build of the same quality. If I had the cash I would consider it
There is a great thread about it going on 2 other forums. PM me for details. Some guys are buying them and gently massaging the heads, and changing cams before they get installed. I've seen some amazing discount prices already (but they supposedly can't be published).