you can get just as much torque out of a D as you can a B if its tuned correctly, im not sure what the torque limit is for a d16 but everyone says torque is what kills the rods so im sure a 250+whp civic with only 190-220 torque would be alright. also i didnt mean i bounced off the limiter i just meant that i take it right up to the limit, i have my shift light set for 6800rpm so i usually shift by 7,000
Rods bend because of the rod bearings failing. Bearings fail generally because of heat (and also hydrolocking). That heat can build up for many reasons, such as metal shavings or even just dirt in there. Over time the bearings can form a raised spot caused by dirt/debris, which can hit the crank journal. There is supposed to be a film of oil between the bearing and crank journal, but if they're hitting each other that film of oil isn't there. Excess friction = excess heat, and eventually the bearing will break.
Rods also bend when there's too much pressure, ie turning up the boost too high. But in this case they bend due to jumping timing or an issue with fuel injectors (clogged, etc). If timing is off it can dramatically increase the pressure to the cylinder walls. With a clogged injector, the system is starved of fuel, thus leaning out, and also causing issues.
Detonation is what usually causes the biggest failure with FI setups. Detonation is caused by heat and pressure. D-series motors have a slightly higher compression ratio, which means more air to move around, and "more" fuel to burn. I say "more" in quotes because even though the engine is smaller, the ratio is larger, which means more air is being displaced. In return, this causes more heat (this is why intercoolers are highly recommended on any FI setup). When detonation occurs, there's a huge spike in pressure, which can cause a pinging sound, and eventually cause parts to break.
You can get the the same amount of power from a D-series, but for the reasons stated above, they aren't as reliable when it comes to handling boost if they were of equal power and pressure. At least IMO -- I've never built a D-series so I can't speak from personal experience. I actually believe B16 and B20 motors have higher compression over a D-series though.
Oh, and I didn't mean to seem like I was calling you out on the rev-limiter thing, I was just stating that I never really beat on that car. Probably never even brought it to red line more than a coupe times