I see little point to having one. The injectors are designed for specific pressure ratios and if you exceed them you pulse widths become unreliable. And stepping up to 3.5 bar of pressure really doesn't net you that much more flow.
If you want more fuel, the best route is bigger injectors and don't forget the fuel pump while you're at it.
2001 Saab 9-5 Aero
2010 Mazda Miata Grand Touring