Peter,

The engine mount for the IO-520 will be different than for the IO-550. It's basically a modified stock IO-550 from Lancair. Chuck Brenner is developing a conversion kit if you choose to go that route. He also will be testing his tuned exhausts on a Legacy at Reno this year. His e-mail is chbaviation@aol.com if you have any more questions. I did a lot of homework on doing this mod. Contact me any time.

Don Barnes
Legacy 198