I have no personal experience with hoen.
I am ont he audi forums a lot. And when I got my bulbs for that car, (fogs, high beam), there were lots of posts online. I wanted a match for the audi oem hids.
The hoens an the SPPs were both talked about in the forums, and people liked both.
There was a GB on the SPPs, so I tried them. I like them. I liked them enough to get them for the boxster too.
Check out this thread. That is how it compares to the audi hids.
http://www.audizine.com/forum/showthread.php?t=100238
here are some of my pics of the SPPs... NOTE. the audi hids are not as blue as the boxster, so, the SPP bulb looks more yellow than the boxsters hid.
ohh and i also have an optic yellow bulb in the other side as a sample of what yellow looks like.
notice how its almost a perfect match.
now on the boxster, it looks more yellow...
And just a few more pictures in the series.
http://lubrify.com/porsche/lights