The first thing I did when I got my PPK/S about 3 years ago was to put some wood Hogues on. Make sure that the panels fit exactly right (I had to whittle and sand mine a bit) and that they don't interfere with anything. On my gun, if I tightened the panels too much or if they were even slightly cocked when I tightened them, one panel would interfere with the magazine release (making it almost impossible to operate) and somehow I think the panels could interfere with the hammer mechanism causing light hammer strikes. A couple of times I had tiny little splinters break off the inside surface of the panels, but I'm not sure that caused any problems.
A couple months ago I decided to fill out the grip a bit with a rubber Pachmayr sleeve. When I did that, I put the original ugly plastic panels back on because they matched the ugly rubber sleeve better than the wood Hogues. Since then, ALL my reliability problems have disappeared (mostly stiff mag release & light strikes).
The Hogues definitely look good, but I suspect that they were not designed for the S&W version of this gun and I think the dimensions are not exactly right. For a range gun it doesn't matter much, but you should be very careful if you plan on using the gun for SD. And if you start to have mystery malfunctions, I would check the grips before anything else.
