Need advice on upgrades for the Sound System
 

My car is a 2004 G35 coupe with Bose crap system, I currently have an JL 1000/1 with a JL10W7. I won a Sony XAV-701 HU in a contest so Im now planning on finally upgrading the sound system. I got a JL e4300 4channel amp for the speakers since from what've read the Bose amp is the cars weakest link.

So know for the questions

Should I install the Sony HU with the JL amp with the stock speakers?

Which speakers will the 4 channel amp power? 6x9s and front ones? What about the 5.5s?

Which tweeter should I get without breaking the bank?

Will the new HU give me clearer bass with less distortion/clipping?

What cable/parts do I need for this install aside from the Metra DD kit?

Is the Infinity Kappa still the front speaker to get? Or there are any cheaper/better options?

Can I disconnect the 6x9s and power the front and mid speakers with the 4chan amp?

Any recommendations for better SQ in case? I want my setup to have all the spectrum, not just lows and highs.

Any help appreciated thanks, and yes Ive searched a lot but the more I search the more Im confused with options and I cant find the DIYs for my specific case.