You won't see more HP cause the stock block will only do so much either way, but you MIGHT see quicker spool up, but we're talking full boost by 2500rpms vs 2800, assuming you could squease'em under the hood anyway. And yeah, twins might not be better than a single setup, but twin turbo's are cooler.

2000 Rio Red I4 Cougar 200whp & 210wtq at 9psi 254whp & 276wtq with NX 35shot WRX TD04 Turbo, Cut Short Shifter, Strut Tower Bar, 17" ZN Wheels, Roush Springs, Starion Intercooler, NX 35 shot, HKS SS BOV, Full 3" exhaust,StreetFlight Chip