Absolutely go with the full resin kit. I actually did the Hasbro Conversion first, and i plan to do the pipe build later, But for accuracy, affordability and quality go for the Doopys. If you live in the US, buy from their eBay store for the easiest transaction...
My Doopys Build
http://www.whitearmor.net/forum/index.php?showtopic=19500&hl=&fromsearch=1