I recently bought a nice Walther PPK/S .22 to use with an AAC Element2 suppressor and it's a sweet little package. The first pleasant surprise is that the suppressor doesn't block the sights. I also have AAC TiRANT suppressors in 9mm and .45 that I use with a SIG P239 and SIG P220 Combat respectively. Both suppressors block the sights with those pistols. I was thinking about ordering taller sights but then it occurred to me to look at Crimson Trace products and use a laser when shooting suppressed and keep the sights as they are. I was thinking about the rail master pro for the P220 Combat. Not sure what to do about the P239 yet.
http://www.crimsontrace.com/products/type/rail-master-pro/01-4200
http://www.crimsontrace.com/products/type/rail-master-pro/01-4200