Hi Giancarlo,
First off, a 670/Q48 is a solid Score, so it could be enough to get you into your first-choice School. As such, a retest might not be necessary. Since you are interested in at least one highly-competitive School, you would likely find it beneficial to speak with an Admissions Expert about your overall profile and plans. Those Experts should be able to answer your Admissions questions and help define the specific areas of your profile that could use some improvement. There's a Forum full of those Experts here:
https://gmatclub.com/forum/ask-admissio ... tants-124/Before we get to the data in your ESR, it would help if you could provide a bit more information on how you've been studying and your goals:
Studies:
1) How long have you studied in total? How many hours did you typically study each week?
2) What “brands” of CATs/mocks have you used?
3) On what dates (or approximate dates) did you take EACH of your CATs/mocks and how did you score on EACH (including the Quant and Verbal Scaled Scores for EACH)?
Goals:
4) What is your overall goal score?
5) What application deadlines are you currently facing?
GMAT assassins aren't born, they're made,
Rich