Ok, so as an Xmas present to my self, I have ordered some parts to dress up the m3. Clearly the stealth bulbs and painted reflectors are straight forwards, But im wondering if any one has experience installing the v-csl splitters. I have been getting mixed advice, whether it does require screwing or not, whether pilot holes need to be drilled or not, if adhesive is needed, and if so, what type, where on the splitter, and how much.

Basically, how do you do the install? It cant be that hard, but I would like to have all of my ducks in a row for when the parts do come. Thanks guys!

Extremely simple, the adhesive (thin double-sided tape) goes at the top edges of the splitters. For underneath you can screw them on or you can put adhesive. I have seen them installed a few times ONLY with adhesive (top and underneath) and from what I've seen and my own experience you cannot get them perfectly on without drilling. Its really not a big deal. I installed mine twice with drilling and adhesive because you definitely don't want a splitter flying off at high speeds.

-Basically place the splitters on first and line them up correctly to the bumper. Once on, figure out exactly where each splitter will go, use some kind of dry-erase marker so next time you put the splitters back on you have very easy to read guide lines. With them positioned you will know where your screws will go (2 or 3). Mark the points and drill the holes on the splitters off the bumper.
-Ensure the holes are properly made out them up to the bumper again, mark those points through the holes of the splitters on the bumper. Drill CAREFULLY, especially on the passenger side where the windshield washer fluid reservoir is. Once the holes are properly made you can either use rivets (preferably plastic) or actual screws its up to you.
-Before making your final install with screws or rivets you will have to peel the double-sided tape on the edge of your splitters. Be careful to place them in the exact position you drilled holes. You don't want the tape to stick really good really fast.
-I know some people did not do any back and forth and just used a pointed screw directly and mounted onto the bumper, plus double-sided tape. Nothing wrong with this method just make sure you get it right the first time and that's it, remember you will have to expose the double-sided tape at one point so doing it like this can be tricky.

FYI: Eventually I ended up getting rid of the splitters and replaced the whole bumper with a V-CSL bumper because it looks much cleaner but the splitters on the stock bumper still look good. Just ensure you take your time and do it right. Also, Vorsteiner makes a stock bumper with CSL splitter holes that make the splitters fit in like butter just like the CSL bumper which I've seen only a handful of people do and looks great. I personally preferred the CSL bumper with the splitters and eventually went also with the one piece race splitter.