I have had a 115 and now have a 150. Both brilliant engines. BRP Provide agood back up and as long as you get it rigged properly it won't cause you any problems.
If you want a LOT of info about E-tecs being used on the sort of boat you are looking to repower then check out the E-tec owners forum here
Etec Owners Forum
It is hosted by Barnacle Bills in the US and there are a lot of very knowledgable guys on there.
You may want to check out the new 115HO or 130 which are the same as the 115 but with a little more power and new gearbox (on the HO)