An MFI equiped RST if running 100% perfect is in fact probably smoother and more refined than any EFI setup. KE jet is actually a fantastic system, let down only by the fact it is getting old now.

Hence we usually advise if you have no plans to go beyond 200bhp, we would advise having the MFI system fully checked and repaired/setup as appropriate to make good. We can restore any KE equiped car to run as good as new, usually for sensible cost!

If planning to go beyond 200bhp, go straight for cosworth management.

In terms of power for power under 200bhp you will gain nothing by changing the KE jet IF the KE jet is setup and working properly.