Ah, fair do's.
That firmly puts me back in the "No DRL's for me" court I think.
I certainly don't wish to be known as the person who put a big size 12 Doc Martin on your cheque book - but just trying to give a 'reasoned' opinion.
I'm only really looking for something slightly brigther than a side light. A lot of vehicles (with standard Halogen headlight clusters) that use DRL's have an appearance that in reality doesn't look any brighter than a powerful sidelight in the daylight. Examples would be the MY10/11 VW Van range, B8 A4 (non Xenon) and the new MK6 Golfs (again, non Xenon). I'm sure you'll know what I mean.
You've sort of nailed it. OK, if you see a non-xenon Mk6 Golf - on their own on open country roads - then their DRLs
do sort of do the job of catching your eye. However, put the same Mk6 in say a busy city, or even on the open road with other cars - and I've no doubt you wouldn't notice the Mk6. And the Mk6 (and the likes with non LEDs) will become even more invisible as LEDs become more prevalent.
Regarding the facelifted T5 Transporter, OK, they also use tungsten filament bulbs for DRLs - but the main reasons why they are slightly more effective than say the Mk6 - is because a/ the T5 is a much larger vehicle compared to a normal road car, and b/ their lights are much higher up from the road surface, and wider appart - so they will stand out considerably easier compared to normal light heights on cars.
Now I fully appreciate what you're saying and you're factually correct about the bulb patterns and beams etc, but I'll be honest in saying that if that MK4 R32 drove past me in a queue of traffic after a MK6 golf did so with the little yellow DRLs (non Xenon model, say a 1.9 TDI for example), both would be equally noticeable to me I'm sure, as they would be to other road users. At a glance, I don't think one would stand out to the naked eye over the other. In fact, Mk6 Golf's with the Halogen headlights have driven past me before and after looking, I've question to myself whether they have sidelights on or if they're indeed DRL's. When they first hit the UK roads on release, I wasn't sure. They're not striking. They seem less effective than the Xenon based whiter DRL LED strips (like the Golf R + Audi A5s etc...), yet still do a job. This is what I was looking to get in on, as other road users are still likely to immediately observe a Mk6 golf with DRL's on than one without any light output at all, perhaps.
You hit the nail on the head - the Mk4 R32 conversion, and the Mk6 non-xenon are fine in relative isolation - but they are nowhere near as striking as pukka LED DRLs - and it is the 'striking', 'catch your eye' attributes of the LEDs which make them so good at what they are. And whilst the 're-designed' reflector tungsten-filament DRLs on my B7 RS4 (and with an added tweak in VCDS to 100% output - making them whiter than the 'yellow' they were from the factory) IS a big improvement over side lights and the early DRLs (a la Volvo etc) - they still get lost in the crowd when LED DRLs are surrounding me.
You're probably right, it may be a lot of expense for not much gain and therefore I probably won't pursue it, but I'm still confident they'd be a better DRL than my standard sidelights. I've even got some of the best bulbs I could find W5W LED's with a 100 lumen output (after trying 6 different sets as a trial and error exercise) but even they are no better than the original OEM halogen ones during the day.
By all means - if you want to do the mod purely on changing the 'aesthetics' or looks of your car, then go ahead. But I think you already discovered that using dipped headlamps in daylight is FAR more effective than sidelights.
Oh, and just incase you didn't know - it is actually illegal to use sidelights on a moving vehicle in anything other than a 30mph built up area with street lights. This law is applicable in the UK, most of Europe, and indeed even in North America (which is why the yanks call them 'city lights', rather than side lights).
50% of the hi-beam ones (again as demonstrated by the US guy on the Mk4 R32) must be an advantage and an improvement, even if they're not full time, genuine and 'proper' DRL's?
Hmmmmm . . . I disagree. It is simply down to the design of the reflector - even if the main beams are run at 50% brightness, they will still dazzle oncomming motorists, due to the 'spotlight' beam pattern. Oh, one other thing - US headlamps have a very different beam design to our European designs - you often see on the yankie forums where they fit 'E-code' headlamps instead of their (frankly pants) 'DOT' headlamps.
Thinking on my feet, I suppose if you could somehow fit a spacer in the headlamp, between the bulb and the bulb retaining ring (effectively pulling the bulb closer to the rear of the reflector) - then this would alter the focal length of the bulb, and then widen the angle. Or would that narrow the angle even more . . . . . ???
Overall, I know it's a 6/10 result I may get, but that's fine as I'm not after a 10/10 result in terms of quality and true DRL'ness. I won't get that unless I go for something like Robins or the set PND recently posted up - the 4x LED bulbs in the GTI foglight housing which I know you're interested in 
RedRobins DRLs are extremely effective - arguably the best non-standard (and non-OEM parts bin raiding) DRL. But I get a lot of fog, and I personally wouldn't like to loose the front fogs.
Just really want to see those PND posted in action.
