Weatherpack connectors?

[Smokinthehippies]

I used these guys you can buy as little or as much as you need so you don't need a whole kit, good prices and fast free shipping.
customconnectorkit.com

Those guys make the kit currently in my amazon cart.

 

[mrk5]

These are pretty nice. You just need a small tip for the heat gun. Mine is too broad and it melts the heat shrink before the solder.

You can get attachments for the heat gun nozzle to make it more concentrated.

 

[Highpsi]

Weatherpacks are nice. I had a bunch of them laying around from wire harnesses I got for free back at my old job. I used them to build a complete harness on my K10 and they seal up and make some very nice connections. Like many of these folks have said, it is just a matter of buying the right tools to take them out of the connectors and such. You don't have to buy the super high dollar tools either, there's other stuff out there than Snap On..

I used Waytek for lots of connector stuff too:

https://www.waytekwire.com/