As long as my golf clubs fit I am fine on the trunk space. I am thinking about getting that sub along with JL separates for the front and keeping the rears with a little amperage. Do you guys know anything about the Valor 606w indash? I know it isnt the best, but seems to be decent for the price. So, the two amps, the JL components for the front (5 1/4" correct?) keeping the stock rears, the 12" sub with box, the indash and wiring should be near my budget.
I need a bracket for the front components? What about changing the stock mid/high on the door?
Which JL separates are you going to put up front? I've owned several of their lines, and have been very happy with them.
Honestly, you might as well just go with a 5x7 (same as 6x8) and just drop them right in. Again, a purist will usually choose a round speaker because in theory, they produce more accurate sound. I'm not necessarily 100% convinced of that, and it's really subjective anyway, but I did switch to 6.5" components in my Ford. I would definitely choose either of those options over a 5 1/4". You will get more output and better midbass from the larger speaker. Some even believe that you get a little bit better midbass from a 5x7 for that same reason. If you decide to go with the round speaker, you can easily make an adapter plate/baffle out of MDF, sheet metal, or even abs plastic. Some speakers even come with these plates, like the Boston Pro 60s, for example (great speakers!). Some speakers give you the option of mounting them as coaxials (with the tweeter on the mid), which really makes things simple and should sound great. Some people prefer to mount their tweeters higher, and the Mach 460 makes it easy for you to do that since the stock tweeter location is in that pod by the A-pillar. I'm not sure what size the stock tweeter is, but you should be able to make the new one fit. If you have the patience, try it both ways. There are benefits to each location, and every vehicle/speaker reacts differently, and ultimately you get to decide what sounds best to you.
Man, I just realized that you said your car is a vert. I defintely think keeping and amping your rear speakers is a good decision. The extra volume will be nice when you're jammin' down the freeway with the top down. If they don't compliment the fronts well, you can always upgrade them later. To keep your stage forward, back down the gain some on the rear amp channels, or use the fader in your head unit.
Valor is a Chinese company that has only been making car audio stuff since 2003. It's cheap by design. I can't urge you enough to stay away from brands like Valor, Dual, Boss, Sony Xplod, etc. The head unit is where everything starts. If you put crap sound into your amps and new speakers, you'll just have louder crap. If you find a double din with built-in nav and a long list of features for a really cheap price, it's likely too good to be true. I checked out reviews for that head unit, and some of them are pretty scary.
With your budget, I'd choose a nice single din head unit and use an install kit to fill the gap. It can be done easily to look nice in your car. If you really want a double din, shop around, consider adding nav later, and/or go ahead and splurge to get a qualityy unit with everything. It's not hard to spend your entire budget here, which is why I suggested a good single din. If you ask me 100 times, I'll recommend an Alpine 100 times, although Kenwood, Pioneer (stay away from their really cheap stuff), Eclipse, and Clarion are all well respected brands for head units.