I was using the 45 degree defence with the HL StuG and the Tam Tiger couldn't hit it from anything over 10 feet or so out. Rotate the StuG and blammo. It's more realistic with a StuG (or a Jagdanything) IMO since the actual hull has to pivot and duck the shot, not just turning the turret. It's like turning you head to avoid a grenade, It can't hit me if I don't see it.

The DBU uses 4 IR sensors, which I suspect is in the TBU as well. At $100, I wasn't about to look inside it.
I did crack the top off the $11 HL apple (It'll be obsolete to me as soon as the DBU arrives) and it's only 1 sensor with a chromed plastic pyramid to deflect the signal. Pretty cheesy, but it works (kind of sums up HL, huh?)

Just to clarify though, I'm a big fan of Tamiya, I bought the Tiger and M4 back when they first came out and love everything about them, since I recently picked up two TBUs, my sons and I have been using them almost daily. Problem is, 2 sons/2 tanks means someone is left out and it's usually me. I can't justify drop 8 bills on a Tam Panther (+ another $200 for Tx/Rx and TBU) no matter how much I want too. I can justify $130 for the HL Panther G to get me in the game and any of these DBC/Mako options get me on the battlefield. And maybe some other folks too, it's all good.