92 Escort Cutom Exhaust

I am planing on modifying the standard exhaust system that is fitted to my UK 92 1.4 Escort. I have already had the silencer box on the front pipe cut
out and replaced with a straight piece of piping (welded in) to increase ground clearence due to lowered suspension. I'm keeping the standard middle section with silencer, and putting on one of those fancy straight through back boxes instead of the standard unit.
Will this be OK or am I modifying the system to much that it will case running problems (ie back pressure, fuel consumption, power output). I know I will get a better sound from the car but will I get crap fuel comsuption figures and/or an engine that will not run to well due to the reduced back pressure that I think I will have with this set-up.
Any help will be gratfully received.
Robert remove "nospam" on Email replies

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