Here is some things to consider.
As far as I know the SLU does in fact slow down the tank when it has been hit. SO this should not be a concern for you. I wish they had a standard 5 pinout arrangment so the Tamiya sensor could be used. At the end of the day it is that sensor that evens up the systems.
Tamiya is Tamiya. Good quality, accepted, but kind of falling behind the cottage systems with respect to sound quality and variety. I appreciate you kept the price of the Tamiya apple in your comparison on the Tamya system. Many people forget to do that in their cost comparison.
The Benedini and EL Mod packages give you that ability to change the sounds they produce to match the tank you run them in. This makes the whole idea of swapping the audio system between tanks a real option as I demonstrated on the video. So when you factor this in the equation you can see that your total hobby dollar for sound can realistically be spread over a few tanks instead of having a dedicated sound system to just one.
The installation of the DBC3/Benedini is not as invasive as other systems. i.e you can easily remove it and the stock electronics are still there to function like normal. This is an advantage because the tank is still usable even when it doesn't have the Sound and IR modues in it.
Working with Darkith's blessing I have ramped up production on the DBC3. These are now being factory stuffed so you should see a slight price reduction on the RTR DBC3. I just accepted the first two samples, and succesfully function tested the module . I purposely keep manufacturing in Canada. SO the DBC3 is now designed and built in Canada, creating a very slight infintisimally small increase in the domestic GNP. I have gone to pin connections that use servo cables. This does away with the fragile wire soldered directly to the board, and gets away from an inherent weakness.
Also Darkith still sells sthe DBU kits for $15 which is still the cheapest way to add an IR sensor to either Tamiya or the DBC line of IR modules. I personally only have one TBU that is used when in club battle. I can only battle one tank at a time, so one TBU is all that is required for complete acceptance at a club. For goofing around in the back yard I use the low cost DBUs. I have also modifed the HL receiver with LED's. I used one of these at Danville, and people were lighting me up like a Christmas tree, so no one complained.