well firstly the SWS and TWS are just like a package that has stuff on top of the rifles where the LTR and P are just the rifles themselves.
As for a good place to get them. A suprisingly large amount of us on this thread got ours over at *** (wow that actually got blocked! lol), just google it.
A L B E R T A T A C T I C A L R I F L E
there... I said it...
As for the ammunition, I have mine in .308 and prefer it over the smaller .223, but a lot of guys here like the .223s too for shorter distance target shooting. But I like it in .308 as I find it a more versatile round as well as good for hunting. They are both common rounds that can be found for good prices and are easy to find reloading stuff for. The .223 being much smaller obviously has smaller recoil if that is important to you. It is also a little cheaper to reload mainly due to less powder and smaller products being used.
Both are accurate rounds that provide a ton of fun for those that shoot them.
You will probably also want a bipod, good scope, rings, base, etc. You will get a million and a half different recommendations from users.
A popular scope for the rifles is the Leupold Mark 4 tactical scope. If you can afford one Skullboy with be the first to jump on recommenting a Schmidt and Bender (the farrari of scopes one would say)
I personally have a Tasco Super Sniper. Great scope but hard to find in Canada as it is not available here.
There is also nightforce which is also quite popular and zeiss for the more pricey ones.
A popular cheaper scope is the Bushnell 10x mildot.
There are a lot of rings and bases out there, the better and more expensive ones are the Badger Ordinance bases and rings. Leupold has really good rings as well (I have) Ken Farrel is also a good base maker and there are tone in this area so i'll let others fly at it.
For a bipod, I have a versapod, and hate it so I recommend a harris for sure, which I will be switching over to after I can sell my current bipod and afford a good replacement. Hear that guys?? I give you first dibs on a 6-9 Versapod tilt that i'll put up on EE once i figure out a price (good condit I just don't like the fit as much) pm offers if you want.
Hope that helps you out Critter, good luck and happy shooting, if not now, maybe soon!