If I'm honest I see clio upgrades in 3 different worthwhile conversions and prices.
Conversion 1 - ITBs roughly 200bhp. This is the cheapest option and gives great results, the only downside is when you want more power every additional mod (cams,headwork, high CR) is both expensive and moves the power band/ peak power further up the rev range.
Con 2 - Supercharger conversion on stock bottom end betwen 240-260bhp. This has to be the most cost effective conversion out there, it literally is a bolt on conversion and gives results upto 260bhp it also produces torque in the region of 200-215lb/ft so it's not going to be a gearbox killer neither (unless your names Ben "give it death everywhere" Stevo).
Con 3 - Turbo on low comp bottom end over 400bhp (but mostly around the 260-280bhp). This is easily the most expensive choice, the fact that you need a full strip and rebuild just to have low comp pistons and forged rods fitted means that this part of the conversion alone will be 1K+, then factor in a new cam belt, aux belt, headgasket, new oil and a filter and you can see how costly it is before you've even bought your turbo, intercooler, pipe work, injectors, ECU etc...... As you can see the amount of work between this and the other conversions is a fair amount. It's saving grace is the choice of turbos out there and the fact that 400+bhp has been proven and that it produces a lot more torque than the other conversions (both a good and bad thing).
So there we go, if I was the OP I'd save a bit more cash and get a SC kit, If I could turn back the clock 12 months my car would be the only supercharged Trophy in the country rather than the only turbo'd