Is there any limit of MacBook HD in terms of storage and/or speed? Apple store only provides up to 200G/4200rpm, or 160G/5400rpm. So, 1. Can I replace mine HD with a 250G/5400rpm? 2. Can I replace mine HD with a 7200rpm HD? I always think the larger of storage the better; the faster the better. Is there any shortage of using a very large or fast spinning HD?