Skusto,
There is a pretty useful thread in the boating section. Good pics as well towards the end.
http://www.ausfish.com.au/vforum/sho...light=kevlacat
There are good options for a transom mount - off the pods or the transom directly depending on the transducer you choose. If you want to go with a wet box the M260 is still a great piece of kit. Cutting a hole in the floor and installing a wet box is not hard at all. Pretty minor cost as well. Would have been less than $250 in total including the deck plate and the strengthening of floor around the hole. Mind you this is money you could put towards a transom mount transducer which if mounted correctly should give you superior performance eg TM260 with a bracket arrangement as per the thread i have mentioned above.
If you have not looked at chirp then I'd suggest you give it a really hard look. Cant go wrong with the Furuno but chirp is definitely impressive in terms of finding fish.
cheers
Michael