Bonehead, as a former Vipar owner, I'm going to give you some food for thought.
Vipar is a UK founded company,
http://www.viparled.co.uk/collections/series-b-1
that is a basically a reseller of this company's wares.
http://evergrowlighting.com/product.asp?id=58&class=NOVA LED Grow Lights
Vipar UK sell 2 models and that's it.
VIPARLED-USA is a Ebay reseller, whose connection to VIPAR UK and Evergrow are vague. Maybe Vipar UK would like to say something here? Anyway if one was to look at what ViparUS is selling they don't seem to be selling any models related to the production models coming out of Evergrow, who happen to be a good budget panel maker and who make production parts and/or done some work for other makers including at one time or another A51. Now VIPAR-USA looks more like LG stuff to me, but could be anyone. I just really doubt it's coming from the Evergrow factory and if you really want to be sure your getting some kind of value, you should find out a bit more about ViparUS. Having said all that, you might as well try to talk to Evergrow and get it from them directly. Alibaba perhaps?
Just remember, the extra money you'll spend on electricity running that panel is going to pay for the A51, which will be cheaper to run in the long run, so do your best to get some more cash and grab an A51, which is a purchase you'll be happier about. Plus you can sell an A51 a lot easier than selling some mystery budget panel if ya need to.
And that Vipar panel will not flower weed in a 4x2 IMO. No way.
Good Luck Bone and Be Safe.