EDIT: Answered my own question now.
For anyone else wondering, the difference between 172 Cup Turini wheels and 182 Trophy Turini wheels is the offset. 172 Cup are ET38.5, and 182 Trophy are ET45. The wheel size is the same at 7Jx16".
The difference in offset is therefore the same as putting on an 8mm spacer. Many owners of ET45 Clio's put on spacers larger than 8mm for aesthetic and brake clearance reasons. 172 Cup wheels can fit a 182 fine, and 182 Trophy wheels can fit a 172 fine.
The 172 Cup came with 195/45/16 tyres, and the 182 Trophy came with 205/45/16 tyres, but owners of both swap freely depending on cost and handling characteristics.
Important thing to note is that when running with spacers (or lower offset wheels) and 205 width tyres, you cannot lower as much. For maximum coilover y0 lowering you want ET45 offset wheels, no spacers, and 195 width tyres.