The Carolina Panthers really went after it this offseason. Everyone knew they had plenty of areas to address in the offseason, even after a nice improvement during the season. They overachieved, which was impressive, but it didn't remove the need for sweeping upgrades. The problem was that they just didn't have the assets to really attack those holes. Picking 19th in the NFL draft is good when you're a playoff team, but not when you still need top-end prospects. They also had a little over $10 million in cap space at the outset of free agency. Yet, they managed to really address almost every major issue they had in both free agency and the draft. They went "big," as CBS Sports insider Zachary Pereles described it. Pereles noted that big here has two meanings. First, they went big in terms of the contracts they signed. Jaelan Phillips and Devin Lloyd were legitimately huge signings with substantial financial investments by the Panthers.…