I have a pirahnamax 170 and I recently ordered a mounting br a key for my tm from bps. Said on the site fits all transducers paid 30$ for it but I found out today it will not work on mine so when I get it it's going right back. So instead I ordered a puck transducer for 20 dollars more. Was wondering if the puck will do as good as the transom mount one that came with it. Thanx again guys