Why are you looking to change I.e. what do you want that you can’t get with the current unit?

Hi, sorry but is your transducer standard with the Unit or a 600 Watt after market one? Cheers Den

I am running a Lowrance HDS Gen3 with 600W transducer and fitted this kit to fish at 300+m. It works very well. I can get bottom to around 550m, but finds fish beyond 400.

Hi, thanks lads will stick with what I have got at present and see how it goes. The head unit limits the transducer to 250 watts RMS and the up grade is a bit to steep. at present. Thanks again. Den 

OP how much you want to spend?

You can spend $2k extra for LIVE transducers now, Garmin are the best in the biz at it. Just youtube livescope. You can literally see a kingfish tail push to take off after your lure if its in front of you. YOu can also move the angle so you get live fish under the boat.

Traditional transducers show what you have run over as such. Nothing wrong with that.

Id only recommend livescope etc if you are into gamefishing a LOT, kingis, tuna, marlin etc. Yes it works for everything. but you dont need to spend that just for bait fishing or finding a pinnacle and fish.

Get the most powerful unit you can afford. 9"+ for split screen gps/sonar.

Lowrance is the only other company to come out with live sonar, called livesight, but by the time you want something better livesight as they call it should have improved.

One thing regardless of all, I much prefer clearview/downscan over old school sonar 2d arches. Clearview etc imo is much more accurate. Its called downscan in lLowrance and of all the reasons id buy lowerance would be downscan, it shows a lot of detail. Im not sure which models offer Downscan as Im not a Lowrance user.

After having look around the cheap hook systems use downscan. 

Clearly the HDS systems are nicer, but wow Lowrance systems are not cheap.