I want to get some new 17'' alloys for my (2000reg) clio and was wondering if they would fit straight on

if u got the wheels for a clio they will fit straight on

If you buy the right sort they should.

2 factors:
(a) the hub - number of studs etc
(b) the wheel arch - you might end up having to have some ultra-low profile rubber-band style tyres.

yes it will fit perfectly in the clio with not problem but dont put eibach because you will have alot of problems with driving it and with 17'' you can put the wheel 205/35/17 and with not problem you can go and have fun with does alloys