installing door upgrades

[mk3 tdi]

would appreciate some guidance if anyone can help.
I am wanting to put some kenwood 3 way s in the front door and have just removed what looks like a component from there - this is it

[mk3 tdi]

now these have a wire attached which leads to a normal door speaker clip as in pic.

the + wire has a blue thingy in there as below


this is the capacitor/resistor close up.



does anyone know what this is and whether i still need it if i am installing 3 way door speakers.

ps i will not be using the door tweets and will not be connecting them if that matters at all?

[w0ffle]

p