It depends on what you want to do with it really. Do you want to do a historical preservation & resotration? Or do you just want it to look correct for the period and take it to the range and shoot it all day? I've unsporterized two No 4 MK I's so far. It's a fun project for me, and I like bringing old infantry rifles back to their battlefield glory. Hey, some people rescue dogs, I rescue old infantry rifles. Plus, it helps me understand the rifle a lot more from an armorer's perspective when I tear that thing down to just a barreled receiver and piece it back together. But mine are not historically accurate in that they do not have the original stocks that it came from the factory with, but I've at least made them look like they did when they were delivered from the factory. Eventually I can shop around and get wood with the factory correct markings at least. But in the meantime, they look good and they shoot. At least the bolt, receiver, and barrel serial numbers match. I paid $110 for a sporterized 1942 Savage and $170 for a sporterized 1948 Fazakerley. But I was able to keep the costs low for unsporterizing them by shopping around for parts like previous posts have already suggested. Between Numrich, Sarco, Buymilsurp, Ebay, Gunbroker, BRP Corp, and stuff I already had laying around, I scrounged up all the pieces I needed relatively cheap. The biggest costs were the stock sets and the magazines. Sarco still has stock sets for $39.95 for a No 4 MK I. I've gotten two so far, and was happy with both sets. It took some TLC and raw linseed oil to bring them back to life, but it's worth it and they look great now. Of course, you'll still need to get all the metal accoutrements though. And BRP Corp has magazines for $28, still a steal compared to what those things typically go for on Gunbroker or at gun shows.
I do agree though that generally you can get a nice No 4 MK I much cheaper
complete if you shop around rather than if you bought a sporterized one and tried to unsporterize it. Of course, there are exceptions to everything. It just depends on what you want to do and what you are willing to spend. Financially, it always makes more sense to buy the rifle complete. But if you have access to the resources to unsporterize one...then I'm all for it.
http://e-sarcoinc.com/4enfieldstockandhgsetused.aspxhttp://www.brpguns.com/products/SMLE-No ... on%29.html