my wife got me a 798 ci hd di unit I like it a lot.i was told it has a dual plus transducer that is 83/200.i was told to get the best di and si I will need to buy a xnt-9qb-90 transducer quadrabeam plus to get 455.is it worth the money to buy it and will it show better detail.thank for any info you guy's can give me.