as long as the wheels you buy are 4 x 100 (4 holes in a circule of diameter 100mm, aka PCD), and 60.1 centre bore (the diameter or the centre circle that sticks out of the hub that the wheel will basically sit on!). Then the wheels will fit!!
NOTE: 13" wheels wont fit over even the smallest of brakes so dont go lower than 15" wheels, and 17s look guff so dont go over 16".
ANOTHER NOTE: if youre buying after market wheels, they usually have a huge bore, then you get a plastic spacers that will match the bore of the wheel to that of your car, make sure you get these are otherwise the entire weight of the car is being taken by the wheel bolts, which is ill advised!
the only other thing worth looking into is the offset. This will be stated as ET38 (or another number), the number states how far the bolt face (the face that meets the car) is from the centre. in my case, 38mm towards the outer face of the wheel. which is pretty much standard for renault wheels, i wouldnt deviate much from that number when picking wheels that are 6.5/7" wide, (most 15" wheels).
ALL 4 bolt renault wheels will fit as they stick to the same fit, (clio v6 and new megane wheels wont).
As for brakes, theyre pretty much identical for the entire clio non-sport range, and are only slightly bigger for the sport range, both of which will fit under the wheel with zero need to touch the brakes at all!
sorry to go on, but i hope this helps!
Also, there is only 1 shop that sells RS grills, thats renault!
but they crop up on the CS for sale sections all the time!
but please dont pay too much for them, many people try and get more for them than renault charge because theyre such a sort after mod!!