Jellybean,
I have prior spoken with J.D. about this issue. He will tell you to just order the parts from Remington LE. http://www.remingtonle.com/support/service.htm
Part 10, Carrier Dog Follower Spring
Part 21, Milled Extractor
Now for my 0.02. From what you tout as your use, the 870EM will suit you just fine without the $15 + 10 shipping parts.
As others have advised, you will get more years of service with an Express shotgun than you’ll likely require. If you actually end up using the -heck- out of your Express, replace the magazine spring every couple of years (go with Wolff springs, an upgrade from OEM IMO). Keep an eye on the Magazine Follower. If it shows wear or becomes chipped or warped, replace it, also with an aftermarket upgrade. Break the extractor, which isn’t likely, then replace it with the LE milled type. Carrier Dog Spring gets weak, replace it.
I’m no SG expert. My only claim is that I have used the 870 platform for 30+ years, both for sport and profession. I own 'em all, Express, Wingmaster and Police. I have my opinions and preferences. But, having the Express in my hand if a situation goes south wouldn’t break me out in a cold sweat.
You near the best part of Virginia… SW? If so, shoot me a PM. Maybe we can take a range trip.
I read your post and assume you read mine. This a technical sub forum so we in this thread are trying to provide the OP technical information on the subject matter not personal opinion.
As I said before, I own an Express and it is a very serviceable shotgun, but it is not near the quality of the older Police models. I would not care that much about it being an E or P if I were buying a worked up custom gun. But if I had my choice of a new Express or a police turn-in 870P for the same price (and they are the same price) I would take the 870P wihout hesitation.
The finish alone is worth the money to me. I’ve seen old, old (before they were even designated as P, and were just “wingmaster riot models”) Remingtons that still look good. These are guns that were in servie for a PD for 20 or so years! My Express has lost a substantial amount of it’s finish from gently placing it in the closet.
That $300 used P model would also not lose value, as I would be lucky to get $175 out of my Express on the used market if I were ever inclined to sell it.