I am currently looking at purchasing a used 2012 Nitro Z7 sporting a 150 ProXS Optimax. I was able to physically inspect the boat today but we weren't able to run it so a follow-up visit will be needed...maybe. I observed welds on both sides of the lower unit that was reported damaged when the lower unit got pinned in rock/boulders due to current. How can I evaluate the repair or should I simply walk away and keep looking? How much would a replacement of the lower unit cost? The boat also has some gouges and scratches of the gel coat along the keel and hull (beneath water line) but they appear to be something I could possibly repair (DIY project?). Any words of wisdom or guidance is appreciated!