I do have two of these bueaties one has a SuperTiger61 and the other has a Fox75 They both have a pitts style muffler. The one with the SuperTiger I have converted it to a bipe. Of course I found out that I will have to cut two bays off of each wing on each side. Last flight it took me about 15 mins to get it down safely. With all that wing it just would not come down.[] It even could catch thermols if you can believe that. And I have wittenss to that. I have had it at the Sig fly in but at that time had not flown it yet. But everbody loved how it looked.