One things I thing would be a good move, is to T the fuel line after the fuelfilter to feed the rails individually.
Thats how I set my car up, so far on stock feed/return. Using a single summit SS fuel filter which I feel like is a little small but it says it shouldn't hinder the flow. I am also using a single hotwired Walbro 400lph (non E85 version) Have been using it for about a year, cant complain seems to do its job.
Haven't gotten to push far on this set up yet, its at 20-21psi on 16Gs and adapter plates. I am using a LT1 GM maf, OLD MAF-T, SAFCII, and ITC, controlling RC1000 at 40psi base pressure, The lowest fuel pressure setting I can set it to, most likely due to the OEM return line restricting the back flow to the tank due to the small size. But car starts/drives around like stock. At WOT I am pretty pleased at the performance, even tho the AFRs are REALLY RICH @ 10.8-11.0. I am also on the stock ignition, just wires/copper plugs gapped at ~.025",
Not sure if this applies but the DSM ignition system is very similar to the 3S system and I have been able to squeeze 37psi so far on a completely stock ignition system on my DSM, so personally I would not get an ignition amplifier until you encounter a blowout problem that cant be corrected with different plugs and gaps. Every cars ignition system is in different conditions.
As far as people having problems with the internal gates blowing open, easiest thing to do would be to install helper springs! I don't have those yet but if I end up having an issue at 25-26psi I will put them on.