I recently changed the exhaust system on mine. I went from full UK spec, to a 98 Spec Integra JDM 4-1 manifold with 2.5" collector, hi-flow CAT, and Spoon B pipe & N1 back box, and the car has really come alive.
Changing the UK manifold for the JDM 98 Spec one, really made a big difference, without affecting reliability or build quality 8)