The Reward for reading Shnayim Mikra:
All those which fulfill the Mitzvah of reading Shnayim Mikra by its proper time are given long days and years.
Sparks of Kabala
Reading Shnayim Mikra merits a person to draw down a spirit of purity and receive the extra soul [which is given on Shabbos]. He is then called an “Adam” which is the highest term used to refer to a human. This is hinted to in the verses “And Adam called Sheimos” Sheimos is also the acronym for Shnayim Mikra Echad Targum.