i was able to change out the front grills on my lci e90 this morning in like 10 minutes after watching this clip on youtube a few times.
but its even easier than the video. i was able to stick my hand between the front piece that you pull out slightly and the body of the car.
so i was able to just stick my hand in there to unclip the bottom 2 notches. then i used a screw driver to unnotch the top 2 clips. just make sure to pull the grill in an outward directions as you unnotch the clips.
once theyre out, just slide the new grills in.
even though the video is for the 135, it is the same on the lci e90. this was a lot easier than some of the other DIY's on here that i read. also the other DIY's didnt seem to be accurate for the LCI e90 as for the clips because there are only 4 (2 top, 2 bottom).
i bought my grills off ebay from this guy,
http://myworld.ebay.com/creativemotoring
they were shipped very nicely and fast. parts were exactly as decribed.