Personally, I think the PIAA silicon blades are a waste of time and money. I didn't find it any more effective than a regular blade even without the application of Rain-X.
Single best mod I did was fitting the MK2 Espace/Movano blade with the integrated sprayers. The regular style blade seems to work a treat and doesn't miss any of the screen and the screen wash actually goes where you want it, instead of into the car or over the back somewhere.
So many threads on this! I seem to have posted on most of them..
On my 4th wiper; the orig VXT one, then the PIAA, then a curved normal, now finally the spraybar mod. I had trouble getting the tubing (ended up with clear, not black, from B&Q) & great difficulty installing (solved when I realised you could cut the existing tubing with a pair of scissors and just insert the smaller tubing directly into it, with no need for adapters - isn't clear that the Renault SprayBar uses a different size of tubing).
Conclusion - this is the best so far, although I STILL find the top half of the windscreen isn't scraped as hard as the bottom half (but at least I can get some spray directly on it). Haven't found RainEx much use really; tried doing just one half of windscreen and the difference is between smudges/streaks vs tiny droplets.
Need all the visibility we can get in these cars...