I have seen mixed reports from people with the ARGtek. Some say it doubles their range, others say it helped a little and some say it made no difference at all. I wonder if this has to do with fcc/ce power restrictions. A benefit of the ARGtek is that it can basically be removed without trace in case of a warranty return. It is also(at least here in the UK with shipping) just under half the price (£50 vs £100). It would be interesting to see a comparison between stock, ARGtek and DBS in CE mode. The issue I have with DBS is that it involves drilling into the remote and at that price you begin to wonder whether you are better off selling your standard and buying an advanced, I don't know.
Just my thoughts on the matter.