SXT is a base model "value" package for a low entry into the market.
SLT is an upper end "value" package that has more "goodies".
Biggest thing on outside appearance is that SXT models will have 17" wheels and most of them have unpainted bumper skins and door mold if equip.
Interior it's all about convenience stuff. There's many diff between all models and some are options..etc so it's fairly detailed.
But don't sweat the small differences because even though I have an SLT, I don't even have an underhood lamp nor a glove box lamp. How pathetic is that?
You can prob get ahold of 08 model year catalogs online and compare the convenience groups with one another. it's just time consuming is all but the info is out there.