I personally think you made a wise choice on selecting a DX959. I have been running one for over a year now and I’m very satisfied with its overall performance. Not only do they have all the whistles and bells (except echo) they can be modified from the mild to the wild. The 959 as well as most Galaxies reacts very well to both Top Gun mods. Once added, your modulation and clarity will be greatly improved. For around 50 bucks installed they are a great investment.
The extra channel mod calls for the addition of two SPST switches mounted to the side of your radio which will in turn get give 100 plus channels outside the normal CB band. You can also have the clarifier unlocked which will allow you to tune your Tx and Rx simultaneously… a real nice feature when playing sideband.
If you want to add an echo you can always have an echo board installed or you can simply add the Xtreme 2018 power mic which will give you a great sounding echo that can be adjusted on the fly. If echo isn’t your thing the Astatic 636L noise canceling mic matches up quite nicely.
As far as having the radio itself tuned I strongly recommend it in lieu of the fact that the factory settings are ball parkish at best. It’s probably the single best thing you can do to help the radios overall performance. An EXTREME WORD OF CAUSION- make sure you use a highly and I mean highly recommended technician to do anything to your radio. There are far more “hacks” out there that will be glad to take your money and slaughter your radio than there are truly reputable techs. I’d put the ratio at least 50 to 1 of hacks versus technicians. Sparky and his staff are on a very very short list of reputable ones.