I purchased one of these (Radio Shack SPL) from someone here but I noticed it's not the current one that sells at Radio Shack. The one I have is the 33-2050 and the one they sell now is the 33-4050. Is this going to make a difference ? I'm new to all this and was just wondering. I still need to get an Avia DVD and then read up some more on how to properly configure everything. Thanks in advance.