I think it can go much higher if we pass the fork without much turmoil, maybe spiking at around $ 7000-7500, but I guess it would not hold at such prices.
The price of bitcoin will always move higher with time but the segwit2x fork is a bit complicated to predict what the outcome would be,it is just my opinion because there is a big corporate backing for that split which is worrying for any trader because of the risk that the price could drop down considerably after the fork will give you sleepless night without a night during the time of the fork.