Upgrading Premium Audio System

[jbrady3324]

I just recently bought 2009 Infiniti g37xs SEDAN w/ Premium and Nav. The bose sound system is just okay. Never been a bose fan. Anyways, I have been out of the car audio loop for years now (moved to home theater audio). I do not want to spend a fortune upgrading the sound but I would like to replace the components that will give me the best bang for my buck (up to $1000 budget roughly). I am using an iPod Classic for most of my music. 95% of the audio is lossless, however I do understand I am bypassing the Burr Brown Dac

What components should I target to upgrade? And what brand/model would you suggest? Feel free to suggest a system for under $1K. Keep in mind that I am not a basshead. I rather clear punchy bass that does not drown out the mids and highs. If I can, I would love to leverage the sub enclosure(s) in the car, however I am not opposed to buying new enclosure(s).

One more question -- I am assuming by using an iPod I will be bypassing the Burr Brown DAC. Are there any IPOD mods that will allow me to leverage the DAC or improve the sound quality?

ThanksJohn