The 197 can be turbo'd - speak to Yozzasport. Apparently the Megane Turbo fits in as they share the same block albeit with different compression ratios.....the exhaust manifold is the same as well but you need the turbo manifold adapted to the 197 to make it work.
Bear in mind the Megane Turbo is not a big boost turbo and will only run 1 maybe 1.25 bar of boost.
Get some stage 1 stuff bolted on. The cats in the 197 are not really that restrcitve - there is 2. The one connected to the exhaust manifold downpipe. This one cannot be removed easily as it is on the bend and 2 pipes run into it and then it becomes 1.
Yozzasport offer a full system from this back, ie that removes the secondary decat before the centre section, the centre box and the rear box. It makes great gains high up but watch out for nasty flat spots low down.
A remap will be needed to set it up right. With regard filters there aren't any good ones simply because of the position the OEM airbox sits ie above the exhaust manifold to the rear of the engine bay. The standard airbox has 2 cold air feeds to it so by removing this and fitting a sealed induction kit with one air feed (and not a very good one) you are making thiigs worse. Fit an ITG or Green panel filter instead and wait until I fit my Clio V6 airbox (BIG) as per the cup race cars and see what improvements that makes. If you can relocate your battery or ft a race battery you can get a good cold air feed from the front grill and maybe the foglights/lower grilles.
There are cams available for a big premium that should boost power to 230 or therabouts as per the CLio R3 endurance racers/rally cars. They are not cheap.
R Sport (the official distributors of all the Cup racecars and R3 rally cars etc) wil be able to suppluy you any poart form the cup racecar including setas, cage, airbox, exhaust, rims, roof scoop etc....
Give them a phone they really do know there stuff and if you want proper RSport parts then best to go direct to these guys.
Good luck
