NEED HELP WITH DAC UPGRADE

I have the BDP-1 as well and just purchase the Ayre Codex about 3 weeks ago to replace my BDA-1 and it's  definitely an improvement all around more detailed, soundstages  more open and imaging is more pin point. Also works very well with my new Focal Elear headphones. Plus the fact that you are now bypassing the soundcard in the BDP-1 which also  improves the sound quality of both units. 
The only complaint I have is the Codex required approximately 500 hours break in. 

I don't  think you can beat the PS Audio DirectStream Dac. Expensive but a value when compared to many others. It's a wonder of breakthrough design and engineering. 

Or the PS Audio Direct Stream Jr at $4k (reduced with any trade in up to $1200 in retail value). Awesome unit

Differences between quality DACs are normally swallowed up by the room. The exceptions are headphone listening and to a lesser extent, listening in a well treated room. When doing critical listening through a nice set of headphones, small differences can show up but deciding what's better is normally a taste thing. Be wary of the shill recommending a 4k DAC.   

Agree!
There's a lot of killer DACs available, new and used, in the $3k-4K range. Auditioning before buying is an absolute must. Especially when spending that kind of money. In this hobby a small improvement in SQ usually requires a lot of money.