I shoot Gold Dot 147's out of mine and have not had any issues. I prefer the heavier bullets, even in 9mm. I guess we all have opinions though. I have not encountered any extra wear, or extra recoil compared to 115 grain.
From my understanding of the HK P7, the reason they say to avoid the 147 grain bullets is due to the gas delayed blowback system. It is not an issue of wear on the frame. The P7 was designed around the 124 grain bullet, and can be unreliable in heavier grain weights. If anyone with more knowledge of the HK P7 finds my information incorrect, feel free to correct me. Hope this helps.