Leave the connectors there and Solder on to a bit you bared (Tap into ) back on the factory wire.. Much cheaper... Then keep you OEM Plug in there, just tape it up to protect it...

In fact a soldering Kit will cost about $20, I got another from Jaycar on sale not long ago..
Just watch youtube and practice a little... I'd suggest a newbie join the wires in an inch apart to lessen the chance of a short...

And as as for changing speakers 4 times, Improving the quality of the install will have much more dramatic and improved effect than swapping out speakers... It would have saved him a few dollars as well..