It is a 100mm cross country bike. No you can't put a dual crown 180mm+ dual crown fork on it. Yes you can upgrade the fork to something better in the 100-120mm range but you also have quick release front wheel so unless you want to upgrade the front wheel your options are limited. Yes you can put a dropper post on it and that I would highly recommend. The bike has the routing to go with an internal so you just have to google or measure what size post you need and buy something cheap off jenson. I wouldn't spend a lot of money on this.