Daily driver..
Ask your insurance company about a Cobra for a daily driver. Your rates, if they insure you at all, are crazy. Now, as a non daily driver titled as a 1965 is about $350/yr with the usual restrictions, and a 2004 titled car is about $650/yr.
20 miles per gallon.... better get a 5.0 with fuel injection.
a 4.6 will limit you pretty much to a Factory Five kit.
Unless your wife is already a street racer, don't give her the keys to a car that can do a 12 sec. 1/4 mile. Or yourself for that matter.
If you really want 300 RWHP, yes you do need forged crap and blueprinting.
See if you can drive someone elses Cobra to see if you really need all that HP to be happy. A lot less HP can still get you into a lot of trouble in a Cobra. 300 RWHP can be very scarry if you don't use it properly. Ask any of the 600 HP guys out there if they ever get to actually use all that power regularly, or at all. A trained racecar driver on a track can barely use 600 HP in a Cobra. Don't under estimate the power of these light weight cars.
Good luck in your search, and don't let any of us intimidate you at all. The real message here is to do your due dilligence, and find out what you really want, prioritize it, and then make an informed choice. Your original post seems a little out of reach if you want everything listed. You are fighting the laws of physics and the laws of economics.