If you've got a 1MB Agnus chip, and switch your system to display the 50hz PAL mode (via Early Startup, TUDE or Degrader), you shouldn't experience any speedup probs at all.
Not sure if your LCD display can handle the region change, but it might. Do a search to see if your monitor is compatible with the 50hz signal first I guess, but I'd venture to guess that yes, it would be fine.
