I took the plunge over the last month add did a total upgrade on the AT 309. I got rid of the aluminum impeller and went with stainless steel. Also got rid of the stock reverse bucket and went with a new SDR. What a difference! First off the stainless steel impelled in is almost night and day in the performance difference. Next to zero capitation with the stainless steel. It put the boat on step with 1800lbs without any issues. The aluminum impeller would have done it but it would have taken some spitting and sputtering and working the wheel back and forth and a whole lot of praying. Empty with a full load of fuel, I am up on step latterly right out of the whole. SWEET!! The stainless is noisier than the aluminum but what I make up in preference, there is no question about it, I can take the noise.The SDR reverse bucket. This thing is great. Now I know what it is like to have an accrual reverse on the boat. Testing it out last night at the lake, moving in out to shore, picking a spot and maneuvering right up to it and backing up and doing it again. It was almost like parking a car. With the different casting of the nozzle I picked up 5mph at WOT and can cruise on step at 300-400 rpm less than the old set up. I was looking at 3100rpm @ 30 mph on the gps. It pretty much put the RMP and MPH the same (ie 3200rpm = 32 mph) Now the big question was it worth the $$$. In the long run, I am thinking yes. If I had to do it over again would I do it, maybe, maybe not. Time will tell. If there are any American Turbine owners out there that are thinking of doing this upgrade IM me and I will tell you all know about this upgrade