RS3projectgrey

Hey everyone, I am new to the Audi world/ RS3. I currently own a EVO 10 968whp and just traded my STI for an RS3. I've read so many good things about these 2.5 engines. I have a few questions,

1. I am sure this is asked A LOT, but what is the most common hp limit these stock internals can handle? I have seen 600whp-680whp and roughly 470tq-550tq , again different opinions have been discussed on these topics so I'd like to get everybody's opinion.

2. I plan to get the following mods, STM titanium 3.5inch single exit turbo back exhaust, STM/ IROZ FMIC, not sure yet what CAI to get. and of course either UNITRONIX/APR tune. What are you thoughts ?

3. Ultimate goal is to max out the stock internals but in a "somewhat happy zone" 600-650whp , what turbo do you recommend? I spoke with IROZ today and they have a killer externally gated large xona turbo set up but I'd like to see what other options there are, any recommendations ?

4. how is the reliability on these cars? anyone having issues?