Instead of buying several hundred dollars in parts why not spend ~$15 on a fuel pressure gauge. (
http://cgi.ebay.com/ebaymotors/FUEL-INJ ... 58877f6236) I don't know this product but instead of loading the proverbial parts shot gun. Take a dive into the EC section of your copy of the Service Manual. A Q is a great project but guessing gets expensive quick, plus nothing is more frustrating than installing something and finding out the problem is still there.
I've done this before, in epic fashion. We all guess at times but testing is really the way to go.
You might want to look into getting a multimeter if you don't already have one...you should be needing it if you want to do this right.