Everybody and their brother will have a different number on "how much boost can I run". You could take a stock KA and run 20psi on it with a T25, or you could blow it up at 4psi on a T78.
It all depends on tunning, the turbo size, fuel, and ignition maps.... there are so many variables.
Some parts of the country get only 91 octan pump gas, others get 94, cool tempatures up north allow more boost, higher altitudes..... you can't compaire boost numbers unless you know it all.
Why not talk HP levels... what is the most HP I can make.... that's full of variables as well, but at least it's somewhat more accurate of a number than 'how much boost'.
with minimal tunning the generally accepted level of 'safe' is somwhere around 7-8psi (this is with just an FMU) Next step up would be somthing like a JWT ECU, that would be safe till around 12psi. Beyond around 14 you can do it but you need VERY tight tunning and big injectors to keep it from blowing up. And by tight tunning I'm talkin standalone.
These numbers are all given assuming 93octan pump gas and a T3/T4 50trim (maybe a 60).
The bent rod thing was my old roommate Shawn, he had 8.5-1 fordged pistons, and 550cc injectors. The car spiked to around 23psi when the ****gate (I mean deltagate) failed. His motor ran out of fuel and detonated. This bent his rod and blew the headgasket all at the same time (it was pretty amazing when we pulled it all appart).
My opinion is that the stock rods are pretty strong, but you can't detonate them or they will get bent.
but pistons are a MUST.... unless you want to be like Jason and just run 14psi on a well tunned KA (his theory is that it's 1300+ machine work and bearings to re-build your motor but KA's are only $300 at the scrap yard so you could blow up like 4 of them and still come out ahead).