Group A Scuttle Induction, but this requires cutting of the scuttle panel
Next I would go for itg filter in standard airbox
Open cones suffer massive heat soak. If you just want noise, they sound great but if you're chasing bhp, avoid.
I had a large filter and like its been pointed out they suffer alot from heat soak.
The best one that is out there is the one that sits in the bulk head
If you have a look on this topic on Clio16valver you will see
http://www.clio16valver.co.uk/forum/viewtopic.php?f=3&t=48495