Hmmmmm, yeah I would probably stay away from Koni. Their FSD(Frequency Selective Damping)/Special Active dampers are very, very nice indeed.....for 500 miles, and then you'll be sending them off for warranty replacements. If they don't develop oil leaks, they rust to buggery. Such a shame as they were the go-to damper for VWs back in the day, with H&R springs and Eibach ARBs. And then new ownership/management stepped in and f'cked with the quality/standards/integrity to save a buck or two. Same old story.
FSD/Special Active, if you're not familiar with the terminology.....think of it as a 'dump valve' for hard impacts. Only a tiny handful of damper makers employ this technology. It works really, really well to smooth out the rough and tumble of crap roads, without the expense and complexity of electronically adjustable magnetic dampers.
Anyway.....VWR, steer clear, it's cheap cr@p. I liked the kit initially as it was more comfy than my knackered OEM struts, but after 1000 miles or so, I quickly came to the conclusion it uses cheap, unpredictable progressive rate springs matched to weak sauce dampers that can't cope with either the spring rates, or the vehicle weight. Too much dive under braking, too much lift under acceleration, soggy cornering and woeful transition from comfort to bottoming out. Probably the worst damper/spring partnership I've ever experienced if truth be told. But that's no surprise given Racingline are charlatans repackaging other companies products as their own.
As an absolute minimum I'd be looking at the B12 Pro kit for a MK6 (not the horrible 'Sportsline' MK5 kit). Anything less just isn't doing the sublimely stiff MK5 body shell any justice at all. Big, fat inverted monotubes give a cornering stability and feel like nothing else....and they came about because the OEM style twin tubes bend like a banana under hard cornering.....hence why all the top kits like Bilstein, AST, Ohlins et al all use monotubes for cornering strength.
Or of course, you could just refresh the OEM stuff for around £500. It's surprisingly good actually, when not knackered. That should go hand in hand with a chassis bush refresh. Nobody likes 15 year old rubbers.