There are MANY tuners in Germany that can produce close to 200 PS for your 118d.
A lot of the guys on the 1er forum have used Marcel from MS Tuning. Including myself. I am very happy with his flash tune. He lives near Stuttgart.
You could also just buy a power box... while not as good as a flash tune... it will give you a decent bump in power. Although on cold start the engine tends to idle funny with them.