Your other questions about DSP, Mars,and tuners.
DSP is digital signal processing. This refers to the processing of analog to digital and back to analog converters (A/D/D/A) used in IF filtering and noise reduction for the receiver among other things. Most modern HF radio's have DSP.
Mars stands for Military Auxiliary Radio System which is a membership required Military radio service for licensed amateurs and you have to remain active to keep your membership.The frequencies used are mostly outside the amateur bands.
In the real world, the term M.A.R.S. is used to describe a radio that has been opened up to transmit fully on all frequencies the radio is capable of. New HF rigs do not transmit outside the amateur bands. When a HF radio is modified for full transmit coverage, it is referred to as the Mars mod.
Built in tuner are nice but they have a limited range of tuning antenna impedance's much above 50 ohms. Most built in tuners that I'm aware of won't tune if your initial SWR is over 3:1. except the high end radios, but you have to purchase and install separate tuner modules. Also if you ever decide to run an amplifier, you need a external tuner behind the amplifier since the internal tuner won't do any good in this case.
Antenna tuners really don''t tune an antenna, all they do is match your radio's 50 ohm output to a antenna system that is not 50 ohms. This keeps your radio happy and it's full output power since many new radio's are designed to cut back power to protect it when it see's a mismatched antenna that is not 50 ohms. But even though the radio may be tuned to show 100 watts full output, your antenna's actual radiated power will be far less since your antenna may still not be resonant to a 50 ohm load.
The best antennas are usually the ones that don't require a tuner so start doing some research on what kind of an antenna system you want. Many times it is a compromise between costs, space available, what your neighborhood will allow, and ultimately what the wife will let you put up on HER house!
Don't be discouraged about not having a perfect antenna especially for multi-band antennas, Most of these work well on multiple bands and many of us use them with very good results. I use a Carolina windom in a inverted V configuration which is a good off-center fed multi-band antenna and on some of the bands, It doesn't require a tuner.