i won't pretend that i race, so my opinion is unfounded there. however, i lean towards the legacy, myself. for a family car, legacy has more room and comfort. both are safe. lgt is easy to modify to get the power you need. ask robson or da rookie and others.
quarter miling is not recommended in any subaru, unless it's a rwd conversion(ESX just nailed a 7.9)...that's my disclaimer. it's done by many, though.
depends on your friend's abilities, but we tend to see more 'abuse' issues from quarter miling than autoX.