1. Can't really say, some mixed posts about FR products but I don't recall seeing a big issue with the Sandstorm specifically. Here is a search on the topic from over 1 year ago that might help you out.
Sandstorm Search2. 25% is okay, but if it's been sitting around for a year they can probably be a little more motivated to sell it too.
3. Can't help with the weights but look up your truck specs and look at the GVWR for the trailer not the Uloaded weight.
4. Yes on the slider, you may not always need it but it's just like insurance if you do you'll be glad you have it.
