I am a high school cross country runner. I have a high arch, run with a midfoot strike and have excellent overall biomechanics. I am currently running 60 miles a week wearing lightweight trainers like the NB 890v3 and the Asics Gel-Lyte33 1 and 2. I have been running barefoot for warmups and cooldowns and runs lower than 7 miles when I have the opportunity to train on a neutral surface. This winter and spring track season I put 1000 miles on two pairs of NB 890v3s, 450 miles on the Nike Vomero 8 (bad experience WAY too much heel), and now 300 miles on the Asics Gel-Lyte33 2. I am well transitioned to wearing my Asics Gel-Hyperspeed 5 racing flats for lots of runs and am interested in purchasing a pair of the Hyperspeed 6 or noosaFAST 2 for the rest of summer training because I really like the super-light feel of racing flats and my heel never strikes ground when I run. Does anyone here have any advice or warnings before I purchase flats?