most the popular splitters will fit when cut down in the middle etc, but they do sit better on a 90 spec instead of the 88 spec, as the 88 spec curves away underneath, whereas the 90 spec stops flat at the bottom making the join neater looking

but yeah, early laguna splitter, early ibiza splitter, iv seen the old skool seat toledo (i think?) style splitter, plus the golf vr6 splitter can be fitted altho iv only seen that on a 90 spec. oh and the centre part of an escort cossie splitter has been done before

not sayin all of the above look good, but iv seen them done