I ran my car with the stock FPR removed, and the Areomotive one on there for quite a while. (No problems.)
Then upgraded to a Walbro fuel pump, bypassed the resistor so the fuel pump has full voltage all the time. (Made it loud at idle.)
The final mod was to change out the FPD (On the back of the rail, near the EGR location.) This seemed to make NO difference at all, but did clean up the engine bay, and simplified the hose routing.
Mine goes straight from the fuel supply hard pipe, to AN stainless line, up to a 180 swivel seal AN fitting, and a AN adapter that uses the stock threads on the fuel rail. (It is a BSP type adapter with an O-ring that seals up the fitting.) Same type of fitting is used at the front of the rail to adapt the Areomotive AFPR and stainless line there. (Everything is AN but the cold start injector which still uses the stock banjo fittings/hose etc.)
No problems so far, but with the fuel pressure regulator mounted to the left strut tower, you can hear the fuel pump/pressure through the body of the car. (Sounds like a thumping noise at idle, but you can't hear it over the car sounds beyond that.)