I have used the search function and it still doesn't seem that clear so here goes. I have fitted a fiesta turbo engine on EFI into my rs1600i and the current spec is:
Standard comp, fully rebuilt motor
Biege injectors
T3
Cvh 35 cam
Front mount
MSD OFAB chip
Looking around this should be around 220bhp? My dilemma is I have a 3" bore Mongoose exhaust fitted but it would appear that I may lose power at this spec level. So the question is do i change the exhaust to a 2.5" bore or just live with it. Any suggestions

 

while you already have it, try it out. if you dont like it take it off and fit a smaller one

 

Unfortunately the car will still be off the road until next year. May just hang onto it until then.