How high can i boost. stock coils
 

I'm at 300 hp right now at 10psi with stock coil packs. how much more can I boost using the stock coil packs before I need something like delco 585s?

How did you get yours to 10psi? I cant get mine to go over 5 right now even with a fuel cut defencer. It used to push 8 no problem til recently it started acting up.

the stock ignition system is good for ~400-450rwhp.

Boost pressure has nothing to do with needing an ignition upgrade. If you do need an ignition upgrade it means there is something wrong with the stock coil packs, the air/fuel ratio is too rich, you are trying to light off aux injection, or you are significantly above 400HP.

The stock FC ignition system does have a limit where you start to misfire, but you're not going to reach it on stock turbo.

I've ran 16 psi on my hybird turbo set up, was just fine. But of course you have to adjust for it.. (ignition and fuel)

I ran a t04z at 18psi on the stock coils, no dramas. Power level was like 320hp but that's because the motor was sort of blown up lol. I have heard that the trailing coil is one of the fastest recharging coils around and is even better then the FD ones? Alot of guys over here replace the leading with another trailing coil. Unsure about the truth of this. How you hit 300hp on a stock turbo at 10psi amazes me though. My stock turbo topped out at around 230hp on an extend port.

The stock FC Leading coil is a significant upgrade for an FD. I have a friend who ran an HKS Twin Power ignition on his GT35 FD and was still getting blow out. I gave him a leading coil off an '86 non turbo parts car and it immediately fixed his misfire.