1). I don’t see any cons at all. I have found out that LSAT scores are kept for 4 years, so if you took it in second/third year it should still be valid when you apply, assuming you graduate at the end of fourth year.
2). Since, the LSAT is not an IQ Test, your score will improve with practice.
3). A good LSAT score is one that can help you to be eligible for admission into most of the law colleges. In the range of 120 to 180, maximum students can be classified into the score bracket of 140 to 160. (Here is the list http://www.lsatprepcourse.com/law.htm )
4. LSAT Preparation Course can be helpful, but very expensive. If you are the kind of person who needs a motivation, you should take a test prep course.
you’re welcome, prego, amico! ;)