I am wanting to buy a Echo cs-590 for general purpose. I purchased a small lot with a bunch of mulberry trees that need to be removed. I am in my small town small engine repair shop and the owner wants to sell me a 590 with 18" bar. I told him I want to buy one with a 20" bar. He said he'd sell me a 24" bar and chain for $70 on top of the $399 for the saw. I said no. Asked him if he would do warranty work on Echo saw bought from somewhere else. He said he would except his pro customers would come first, then equipment bought from his store then my saw months later. I am walking towards the door and he says " You know Echo saws are built at 3000 ft altitude. If you buy a box saw from Home Depot it'll be fine if you just use it for a couple hours but if you use it at sea level (we are in Florida) every week it will burn up. The mix will be too lean." @! Well I've unpacked a couple Huskies working for Asplund and the saws worked fine. Can't say as I ever bought an Echo before, so I don't know. lol Question is- Do I need to adjust carb tune on my new 20" CS-590 for use at sea level?