Its really depends on what your ultimate goal is. Smarty Jr. is a simple tool for the average user that does not need all the funing features of the full Smarty.
The price difference is only 190. 00 but the list of tuning features is endless and will always be growing.
Both products are full code reader in plain text and each adjust the abs for speedometer calibration.
Both products also reduce egt's and should improve fuel economy.
Feel free to ask any questions.
Thank you
Bob