LSAT and UGPA correlate with first year law school success. After that, people start to figure things out so the correlation drops into the unreliable zone.
If you really prepare for law school and get the right advice for how to tackle law school, I think you could erase that advantage. IMO, you should go to the school you like more. Don't worry about your competitiveness so much, you will do fine.
The fact that you have framed your question as you have, tells me that you will quickly figure out how to succeed. The correlation is statistal--which means it predicts the success of a random student. You are not random, you are out there educating yourself and preparing for law school. I was random, I did nothing to prepare. I had average numbers for my school and no scholarship. Nevertheless, I did much better than virtually all of the scholarship students. So, even if you were random, it still wouldn't be set in stone.