It is best to peel your own, but packaged tail meat is a huge time saver and works just fine. If you use the packaged, be sure to add a little water to the fat inside to get all the flavor out. Make a crawfish stock with leftover heads and shells; just rinse off any seasoning and boil them for 30 minutes and strain. A good shrimp stock can be made using dried shrimp (look for them in any Asian market) boiled in water and strained. Crawfish Puree is an optional ingredient that can be found in South Louisiana but virtually impossible elsewhere. Look for it at Cajungrocer.com
or leave it out of the dish.