My Lucky Disclaimer:
This is just opinion not experience--(so when Mike wakes up he won't blame me for confusing everyone hehehe), so read with caution.
First of all, you can screw anything up if you don't know what you're doing. So if you don't know what you are doing, have a professional with a good reputation work on tuning your PFC.
We are not increasing the static compression ratio nor we are increasing the stroke of the engine here, so I don't see why any damage would be done. About the rev limit, 8600 is not that bad since the stock is 8350. You won't go all the way to 8600 anyway, more like 8500 if you shift perfectly. So in operation it's only 150 rpm higher than the stock limit, and you won't be staying there long at all. Of course if you use cheap petroleum motor oil at 8500 you're just asking for trouble. Use RedLine Full Synthetic or Royal Purple.
If anything the PFC prolongs the life of your engine because it measures and reports knock level, so you can adjust your A/F ratios accordingly to keep your engine safe. What's bad for your engine is putting on a high flow Intake
and exhaust, running lean and expecting your stock ecu to compensate for it which it does a bad job of.
On ignition timing, until you know what you are doing don't touch it and your engine will be fine. If you use nitrous you might want to retard it, but one person who ran a 13.716 s 1/4 mi at 1200 ft with NX 75 shot does not retard timing--just uses colder plugs...so do whatever you think is safe.
On valve timing: Again don't touch it until you've been trained. You're basically adjusting the timing of the Intake
valves to allow the engine to breathe better esp at higher rpms so you can get more air in the cylinders. Of course if you allow too much air in, your dynamic compression would be too high and that could cause detonation if your octane level of your gas is not high enough, or if you subsequently did not add more gas for the more air.
So basically: You can get the PFC and see great gains and your engine will still be safe. You don't have to mess with everything until you're ready. Adjusting fuel injection through monitoring A/F rato is where you should start, and as long as you aren't running lean, and causing knock, you should be fine.
Now did that hurt anyone??? I hope not...