You can buy with or without connectors and some places will put connectors on for you. For one system I need Pl-259 at the antenna and N at the multicoupler. From there it goes to 16 recievers and whatever each reviever takes, most are BNC but a couple use Pl-259's. I ususally though just buy the cable and put the connectors on I need. For one it means a smaller hole going into the shop or house without the connector on.
There are several types of LMR-400
Standard LMR-400 solid core multiple layers very stiff
Ultraflex LMR-400 different versions somewhat flexible
Then there is the Ultra Thin LMR400, fairly flexible, usually used in mobile installs
I think the best price I have seen lately was at Kollman Radio or Universal Radio, don't remember. Thats a couple months ago.
I've never used LMR400 and won't until we move from this house. (I'm not going to rewire all the antennas again. Too extensive, expensive and disruptive - whew!) I'm using the RG8X (stiff and heavy coax) and although it's lossier (is that a word? LOL) than the LMR400, there's not by any means, significant loss and I've found it to be just fine for my use right now.
Universal does have a excellent chart, for those who may not have seen it:
In a couple of years, when Don (my husband) and I finally retire and move to Austin, TX, I'll be setting up my "dream" amateur radio setup, along with all my scanners. Then I'll have time to put in the perfectly matching coax, antennas, etc. But, for right now, everything is receiving great for what I want and transmitting just fine!
Oh DUH! I'm using the ultra thin LMR400 in my car and completely forgot about it. It's excellent! Both in reception and in design!
I have it running to my 396XT/remote head setup. It is flexible enough to work it around the edge of the carpeted area inside the trunk and under the carpeted area in the back seat of my car. I'm not sure how Tim routed it to the front but he said it was easy to run it between the front seats and "hide" it until it reached where I have the 396XT located. It's so thin that even using the flexible plastic "wrap", to keep the connector from the remote head together with the antenna connector, is very inconspicuous. Very kewl!
Edited to add: There are a lot of electronics in my car, so if Tim said that it was clean and easy to run the coax from the back to the front of the car, that's a GOOD thing! It's also the first time he hasn't complained about an install in one of my cars! Hahaa