If you're old enough that insurance isn't an issue & have enough money for a decent condition one then get a 182. The parts cost (a dynamique + parts for a conversion = more than a decent condition 172/182), insurance, tax and DVLA kafuffle make conversions pointless. For a start the conversion will cost in the region of £1500 in parts alone. Honestly me trying to convince you to get a 182 over a dynamique is a waste of time
Iff you can afford it just get a Renaultsport version. Anyhow, these are the differences:
Apart from the engine it has:
* Larger diameter front discs
* Disc brakes at the rear too. They're not stunning like the Brembos on the 200 Cup etc but on a circa 1000 KG car they are more than effective.
* Lower centre of gravity
* wider track
* More camber I believe.
* Different steering geometry (don't know what's different I just know it's "revised" and "sporty" according to the clio brochure)
* Firmer springs & dampers.
* Wider tyres
* As a point of interest for a conversion, the damper/hub bolt spacing is different so all the hubs/driveshafts/etc are all specific to the RS models.
Interior:
* ESP
* Traction control
* Climate control standard
* cruise control
* aluminium (effect?) pedals
* Xenons
* Half leather/alcantara seats
* Uprated (to 22w RMS) stereo/speakers (which are rubbish BTW, if you care about sound quality)
* Optional Recaro Trendlines (very rare, about 50 sold IIRC)
* Optional sat nav (again very rare)
Exterior:
* "Cup" spoiler
* Front splitter
* RS grill
* Skirts
* Bumpers
* Wheels
* Twin exhaust
* wider arches
* All the colours are unique to Renaultsport models. E.g. a "black" 182 is actually a pearlescent-ish "black gold" compared to a "black" dynamique which is just plain black.
The dynamique is available with a a few options so one may also have the following: (I'm a bit hazy on these as I've only owned a Renaultsport 182 not a dynamique)
* "Control pack" (cruise control & climate control)
* "Entertainment pack" (upgrades to 22w RMS stereo/speakers)
* I'm sure there are a few more "packs" but they're not very common at all.
Think that's it. Standard clios are great first cars but they're not a performance hot hatch. A 182 is a proper hot hatch. Honestly you're comparing a normal car with a performance car.