A couple of years ago, I decided to replace the bumpers on my 1989 UK spec Carrera Sport 3.2. Having realised that achieving a full pre-impact bumper retro look would be too difficult and expensive, I surfed the web and found this thread, which I read in full and vowed to proceed with the RUF CTR solution. Surprisingly, I could only find 1 UK supplier, of dubious quality, so I duly approached Brad at BWMotorsport as he appeared to be the preferred supplier in the US. He was very helpful and eventually provided me with a pair, plus the nerf bars around Easter '07 (fortunately, the exchange rate at the time was favourable).
However, I didn't get started last year as I had a trip to France in the car during the summer and then other things got in the way. Finally, a year later, I got going and, of course, discovered other jobs underneath the car that required attention, including a bit of rust, so I did a more thorough restoration job and got it on the road again around the end of September. I am delighted with the end result and have attached a couple of pictures - I have never seen another 911 with CTR bumpers in the UK.
I had few problems installing them as they were a pretty good fit, and I did use the nerf bars underneath, albeit with custom made support tubes at the rear, as the Porsche (front) originals didn't line up too well, plus some aluminium sheeting to provide a heat shield between the bumper and exhaust. As my car is UK spec, I don't need the additional (rearmost) turn signals at the front, so I just fitted smoked aftermarket lenses in the holes, which I think looks rather better than the US-style double set of lights. I opted to use the 964 'smile' at the front which works well, although it does sit up a bit - there is presumably a slight recess in the 964 bumper - and was actually a fraction too long, so I had to cut about 3/8" out of the middle and bond it back together. I also fitted very small aftermarket LED rear number plate lights and spaced them to suit my own numberplate.
So, many thanks to all the contributors to the thread - I found out pretty well all I needed to know to do the job from therein. Hope you approve of the end result.