Uncertainty here .
I got a couple of freebies with the QX25 and I took 2 Bass choices.
I'm in new territory here.
A DVi I understand to be "Downloadable VI"
The EXE install gives a bunch of options to go to my Vst plugins folder and I have no clue.
Options are 
1.Full Install, 
2.VSTi, 
3.RTAS, 
4.Standalone.
What do/don't I need?

VSTi for use in Sonar but remember to do the VST scan when launching Sonar next time (in case auto-scan at startup is disabled)

Standalone if you want to jam through it without Sonar open

RTAS only if you also own ProTools

what free instruments are they offering exactly?

Thanks.
The deal is they give you $50 credit to spend on anything if you bought one of several hardware items.
I got the Alesis Qx 25 and the two bass DVI's were under the $50, so free.

who is they? and spend it where? i am looking to pick up the QX61 so any bonus products from a specific vendor would sweeten the deal

The box it came in sent me to 
http://www.sonivoxmi.com/AlesisAkaiDviPromo.asp

"Thank you for purchasing an Alesis or Akai Professional controller keyboard!
The following models are currently participating in this promotion:
Akai Professional - MPK25, MPK49, MPK61, MPK88, and MAX 49
Alesis - Q25, QX25, Q49, QX49, Q61, Q88, and QX61 controllers. Click here for the Alesis Vortex DVI.
To redeem $50 promotional credit towards the purchase of any Sonivox DVI Products please follow the following directions.

cool, thanks! guess its just an Alesis cross promotion.

I have an Alesis Vortex on the way and I went to Sonivox to listen to the DVI demos.
Actually, the acoustic and fender bass both sound pretty good considering the price. Very usable.

Kind regards,
Rick

Maybe I'm wrong but I assumed that these VI were basically the old Sonic Implants soundfonts re-packaged individually w/ a GUI. The Blue Jay Drums in particular. 
 
Another of the bass instruments which I've tried last year also reminded me of an old soundfont I used to use back in the days - same sounds, same options (picked, chorus, wet, etc.).