I have a seat ibiza splitter fitted to the '86 spec S2. The end pieces needed cutting off as it curves round too much, but apart from that, the length is ok. Took the front bumper off & turned it upside down to drill the bumper & splitter together to get it to bolt squarely.
Don't think any splitter will fit straight on bar a ford item. Laguna splitters are too long in the centre section & will need cutting & shutting. If you want one, try Renault to pay a rip-off price or a renault breakers (listed in autotrader normally).