Hello Kelbear1,

Sadly there are no models listed for the XPS in the HigherED section:

http://www.dell.com/ca/highered/p/xps-desktops

The Optiplex would not be the system to get if you had intentions of upgrading to a GTX 760.  I would send it back and get the XPS 8700.  You probably won't have to change out the power supply on this system for the card, but if you do you can use the Corsair. 

Only the Precision Workstations are going to have those big power supplies starting with the T3600.  

Dell Precision Models would be though.

www.dell.com/.../precision-desktops

Dell Precision T1700 Mini Tower

The price on the Precision jumps up pretty quick. I think i might settle on the Alienware X51 as it's within my budget. It comes with everything i need except no free PCI slots for future add-on cards. The other alternate is going for the XPS 8700 and change the PSU and use the GTX 760 card i got already. Any idea what's the power rating on the XPS 8700 PSU? Is it a standard ATX PSU that can be easily upgraded?

It's a standard ATX PSU at 460 watts.  The GTX 760 has similar power consumption compared to the GTX 660 Ti.  Others have used the GTX 660 Ti on this power supply.  You can easily upgrade it though if you need to.  

Thank you so much for your help Kelbear1!

The Dell SMB website now have more models of XPS8700 listed and i will be purchasing the one that has the GTX 660. Got to wait for 1 week for production. That card uses 1 PCI-E  power connector while my GTX 760 utilizes 2 of them. The video card mfr provided a 4pin molex to PCI-E adapter which i can utilize or if possible just swap out the PSU box with the Corsair CX600 i got with me

The power supply on the XPS 8700 should have two PCIe 6-pin power cables for video cards requiring them.  Most likely you will not have any 4-pin molex connectors on the Dell power supply since everything uses SATA.  The GTX 660 Ti uses two also, but the GTX 660 only uses one.  

I'm extraordinarily frustrated by a similar matter, however, what complicates this is that a dell technical support specialist informed me that "any ATX power supply will work on your system."  Of course I realize this is not true, so I pushed the fellow on his answer.  He indicated I could check for an adapter at centrixintl.com or at power-on.com.  I checked both of these and found nothing.  I'm so blasted frustrated over this.  Does anyone know what the pin-out is on the 8 pin connector?

Answered in your other post here:

http://en.community.dell.com/support-forums/desktop/f/3514/p/19505800/20423650.aspx#20423650

Bev.