Assume that the change is permanent and thus the consequences or benefits, as the case may be, also are. Choose carefully!
I can comprehend the "ignorance is bliss" argument. Especially in a Universe composed of 75% dark energy, it can be nice sometimes to be numb. At the same time I can also see a myriad of benefits and detriments of having an extremely high IQ. I personally don't know if I would choose to raise, lower, or maintain mine at a comfortable and familiar 135. But I've always thought it was a good question for reflection.
HOW the world changes in accordance with level of intelligence.
ETA a Sidenote: I highly recommend to everyone, on this topic, an excellent fiction book called Flowers for Algernon by Daniel Keyes.