Concerning the ETH compression ratios, they are higher than the other engines previous to this model. Moderate timing advance should not raise this to the 'breaking' point unless used in conjunction with other power increasers. The added heat saturation of increased fueling and turbos operating out of the map can compound the problem, thus causing you to reach the 'breaking' point sooner.
The heat saturation in #6 is a result of the engine design. I think Banks did a good job of addressing this problem on their sidewinder truck. They did some custom work on the intake runner of the head to increase flow, and cooling of the intake charge air. Notice that on our engines, the intake runner piping to #5 and #6 in enclosed in the head more by the design of the head, therefore it has more chance of being warmed by the surrounding metal and water jacket in the head. Thus #5 and #6 receive warmer charge air than the other cylinders to some degree. We all know that the temp of the intake air affects in cylinder EGT. Now, add the fact that the cooling water in the engine comes in from the front and exits the front, therefore the colling water reaching #5 and #6 is already more heat saturated when it circulates through the back of the block than in the front of the block. All of this makes for some difference in EGT temps if they were measured in the exhaust runner of the head at each cylinder of some value (lets say 100* +/-). The EGT value your gauge says is just an average of whatever is flowing past it in the exhaust manifold or after the turbo, depending on thermocouple location.
Aluminum expands and contracts more than steels and cast irons due to temperature fluctuations. That is why the piston in #6 commonly swells up and galls in the bore. It literally expanded until the skirt starts smearing agains the cylinder wall. In a more extreme case, as with excessive fueling, the top will start actually melting and putting melted Al in the valves and exhaust runners. The new ISBE engines have added enhanced piston cooling j-oilers to better control heat buildup in the pistons. Also the new ISBE head flows better for both intake and exhaust. All combines to provide better heat management and in cylinder EGT control.
If I were to rebuild my engine again, there are some things I would have done differently. Besides the mods I did on this rebuild, I would have taken it a step further and reduced the compression slightly. I had intended to install a . 020 over head gasket to reduce compression slightly. The HG I installed is stock thickness because it is what I got from Haisley, although they do make some taht are . 020 and . 030 over in thickness, but I did not order one at the time because it slipped my mind and I did not want to wait a few days more before getting the truck going again. I had also considered replacing the ETH pistons with some with a slightly lower compression ration, or machineing some off the top of my pistons for the same effect. Of course, this would have prepped me for the baddass cam I want to add at some point in the future. Anyway, lower compression ratio would benefit in the future with advanced timing, propane, and way too much fuel. The combination would help keep it going longer before having to teardown and rebuild again after more abuse.
For you guys out there running stage 2 or 3 injectors, timing boxes, fueling boxes, and large single chargers or twins on ISB engines, I think you are safe. Safe provided you dont try to flog the snot out of the truck while towing, and preferably unplug the timing OR fire ring or o-ring the head. You should have lots of miles of happy driving without problems. Once you start creeping past the 400 HP mark, be prepared to take countermeasures and keep the roadside assistance number handy.
Attention: TDR Forum Junkies 
Did the Van Haisley thing with the 12 mm studs and the PDR 24v cam. 
