huge difference in money from 250bhp to 300 even from 270-300 its not cheap,imo 250 is enough if not too much for a fwd road car, only when you compete your car at events does it make sense to start seeking more power but then you need to start thinkin about sorting other areas ie suspension/gearbox etc so that 300bhp engine ends up costing you twice what you thought it would be plus your gonna need the same money again to get the best out of it with modding other areas
for 250 bhp id stick with the cvh as its a cracking engine at that power level if its 300 your after then you cant compete with cc but unless you spent a wedge on the zt then your gonna make peak power at lower rpm than the cvh and have to keep changing gearbox's every month