First of all, congrats on working for your degree I think the time & money spent will be well worth it in the long run.
Installing BT to disk will be faster, and (in my usage) more reliable than in a virtual machine. I've found some of the tools in BT just work better when run outside a vm. Here's my advice: before doing anything, get a full backup in case you F something up! Assuming you have enough disk space, install your preferred version of BackTrack in a virtual machine so you can check it thoroughly on your hardware. If everything goes well, download your preferred BT version in ISO format, and install on your laptop following the dual boot directions on the wiki.