Sorry I'm into this thread a little late.
I agree with everyone who says keep the Jag. It's a unique guitar with a unique sound. Faded SGs are a dime a dozen...in availability, and tone. Believe me, I've been through this in a big way, you'll kick yourself for the rest of your life if you get rid of the Jag.Even if you are bored with it now and experimenting in different areas of tone, one day you'll wish you had your trusty old Jag back.
Now the Firebird...that's a different story. Very cool guitar.