This is my 4th revision of my project (after research) so I think I am ready to submit it for your consideration/comments ...
My goal is to make a mini-tower on par with Apple's iMac with NVIDIA GeForce GTX 680MX 2GB GDDR5 but with an replacable GPU
Performance on par with iMac 27"
Must work as much as the real thing (Wake-on-LAN, Wake on WLAN, Wake on Bluetooth, Target Disk mode, etc ...)
Must not sound like a Boeing 747 taking off
If possible, OS X will report WiFi as Airport
FireWire 400 and 800 required
Max Budget $1500
Music recording (amateur) , talking GarageBand from 8 to 24 tracks
Games (native and thru Wine)
Dabbling in XCode (hobby)