I have 870 express with a choate +2, and some short stock with pistol grip, and a 4 shot side saddle. I  bought it the way it is.

I want to add better sights all it has is the factory bead. I want a simple sling. I want a budget light.

I am not a door kicker,this is for HD or zombies. I have my AR as HD primary weapon.

So any links will help, and I am on a budget.

Thanks for the help.

http://www.cabelas.com/p-0034586227609a.shtml

I put these on my on my 870 express and they work great, cheap and are easy to install. Cabelas Item:UK-227609.

+1 to this.  Unless you are regularly shooting slugs at distances of 50+ yards, IMHO, rifle sights tend to be way too slow and unnecessary.  Ghost rings are fast than rifle, but the fiber optic bead is faster still.

You'll need a vent rib barrel to install those linked above.  You'll need something like this if you have a plain barrel.

For a light, get a Surefire G2L and something like this and this.  

For a simple sling, get a 2-point quick adjust such as one from Rocky Mountain Tactical or a Vickers sling from Blue Force.

I have the XS big dot sight that glues onto the bead and consider it the cat's ass for an HD scattergun. Ghost rings are great for extended range slug shooting but too busy for HD, IMHO.
The Uncle Mike's tactical shotgun sling can be used as a two-point or HK-style sling and works well for only about $23. Adding the side sling mounting to my Mossberg was only about $10.

Thanks,
Lee

Thanks for the replies.

My 2 cents.  I am not a door kicker either, however I feel if you are going to have a firearm .... it should be the fit for your NEEDS and be the highest quality possible.  BTW, there is alot written on here by GunCat, COSMO556, and JD McGuire.  I take their words as gospel, they have alot of experience and KNOW WHAT WORKS and what will not.... Identify your needs (you did that HD..SHTF) and meet those needs as best you can within your budget.  Also, pattern your scatter gun at various distances so you know what it is doing and shoot it alot (birdshot is great to practice technique.....).YMMV, lather rinse repeat....

1) Dump the Choate tube......(I have one and I was very unhappy with it.  I will not even put mine on the EE.)
2) Bead is ok, WORK WITH IT before changing it out.
3) Add some Uncle Mike's Quick Detach sling swivels, some one inch webbing and tri-glides and you have your sling.
4) Not sure what kind of stock you have, if it is pistol grip, dump it.  I like the SpeedFeed II, high quality for a little money.  There are also Remington synthetic take offs on the EE for $40.
5) There is a light mount that attaches between the mag tube cap and barrel band and had a small of rail.  Put a TLR, X3, M300, Surefire G2 in a 1" scope ring, whatever on it.  COSMO556 swears by this rig.  
I personally tried many different options and I finally broke down and got a Surefire 618 FA off the EE.  It adds some weight, but I wish I had not spent a bunch of time and money on "other" options.  The only other option I would use would be a QUALITY mag tube extension (Wilson, Remington, VANG COMP) with a laserlyte tri-rail or the Mesa Tactical mag clamp with rail.  I have a VANG mag tube and it is great.  Had I not got a deal on my Surefire I would have gotten the Mesa and used my Surefire Millennium on my Vang tube.  Now the Laserlyte is on my backup while the Surefire is on my primary.....

I am also not a fan of the Tacstar side saddle.  Not too bad, I just do not like it.  For rounds on the weapon I like the Specter Gear butt stock carrier with SG CQB sling.  The local Marines have them on their shotguns at the gate of their compound......Good enough for me....

Here is my 870 Express Magnum w/ Vang tube, Laserlyte tri-rail, Millennium light, Speed Feed II (inexpensive stock) and generic 1" sling........Presented as just one option.

So I have shot this weapon and reloaded. I have not noticed anything funky  with the tube. What is the deal with the extension?

The plastic piece that is the end either rattles around or gets jammed sideways when attaching it also the spring was very mushy and I suspect it's quality.  The thin metal walls will also deform VERY easily, don't put those clamps on too tight.  I also suspect the threads will strip easily if tightened too tight...I much prefer the Vang / Wilson with a heavy duty Wolf spring.

My 2 cents, YMMV