I'm not affiliated with, or know anyone personally that works at Thunderstruck. I bought my kit from them and this is my experience:
They will take whatever time is required to help you understand the system and what you need....even if you ask the same question over and over in new and complicated ways as I did :P
I ordered and had the parts on my shelf a year before I was ready to install them, the boat took longer to build than I anticipated.
A newer improved system had come on the market during that year and Thunderstruck took back every item (a year later!!) and gave me a full refund and set me up with the newer kit.
They rushed the parts to me over the Christmas / new year break when other vendors were closed for the holidays as I pressed on to make a pending launch date. oh ya...I sent the returned items to the wrong address. UPS said they would not do a damn thing since they delivered the box to the address on the package, they washed their hands of it.
When I explained this to Thunderstruck they drove over to the address and got the package for me.
I was blown away by the level of customer service and prompt after sales service while I worked thru the installation.
So there you have it, one mans experiences with that company.
They have earned my loyalty and that's where I'll be spending my money in the future.
my install pics are at the blog below if you want to see them.
I ordered and installed the ThunderStruck 10.5 system in my Morgann 33 O/I and could not be more pleased. I went this route because I knew I was going to have to do it myself. What little trouble I did have, the staff at ThunderStruck were there to help with my questions. As others have stated, sorting out prop size and reduction have almost everything to do with performance. It took me a couple of tries but I am now as happy as a clam living on my boat as it doesn't smell like a bus with a fuel leak. It takes me 5min to get underway, 10min tie off when I return. For the do-it-yourselfer, ThunderStruck's system gets a 10 from me!