String Trimmers

I am looking to purchase a new string trimmer and I lie to be thorough when I do my research. The biggest thing I want from equipment that I buy is longevity. I have a couple Echo blowers that have the hard coating on the cylinder bore. Husqvarna's do also have this coating but their website seems a bit conflicting at times and some 3rd party sites do not alway have the same info.

What i am looking for at this moment is:
On Models 322L and 525LST, the Husqvarna website says it has the Hard Chromium plated bore. But the other models in the "525" group are not labeled as to have this. Do the 525L and 525LS models have this plating on the bore as the 525LST does? 

I am leaning towards the 525LS as it has a more powerful engine then the 322L and also has a higher head RPM than the 525LST. I have read several accounts that the slower spinning head (geared more towards torque) creates issues cutting fine grass or other light materials. This is from several different brands offering the higher torque option.

Thank you