Good evening

Im about to get a fender kurt cobain jaguar but its only the body

So how much I good neck would cost

And another question alot of jaguar owners talk about the bridge and that the have installed a mustang bridge or a Mastery Bridge for better results all the jaguars have this issue or only the Squier versions ?

please ignore my username
A Jaguar neck with tuners is usually like $200 because they're much more rare than their Strat/Tele/Jazzmaster counterparts.
Depends which route you want to go, are you looking to have a "Kurt Cobain" clone, or something different?

If it were me, I'd pick up a CIJ/MIJ 66' reissue neck (one of the new B&B ones), make myself a clone of the guitar BEFORE it was Kurt's.....behold, the Martin Jenner Jaguar! Not really a fan of the artist myself, but kind of a cool idea. Check mark 28:09, 29:22, 28:48, and 5:20!

My Current Mains
- 1996 Fender Jag-Stang with EMG Pickups
- 1998 Fender Jaguar with Cool Rails
- 1982 Hondo Paul Dean II (DiMarzio Super II X2)
- 2010 "Fender" Jazzmaster (Home built)
- 2013 Squier VM Bass VI (stock)
Look at Warmoth.com for a jag neck.

You won'y need a different bridge with the KC jag as it has a TOM not a standard Jaguar/Jazzmaster bridge.

I don't think a mastery would fit.
'91 Epiphone by Gibson Sheraton JLH
Godin 5th Avenue
Hughes & Kettner Tubemeister 5
Hughes & Kettner 1x12 w/ Vintage 30's
Fender Mustang II
MXR Super Badass Distortion>Boss CE-5>Boss OC-3> ???