Has anyone used Slip Graphite Lubricant as a finishing product on cast iron exhaust manifolds?I've stumbled across several sites that have used a graphite lubricant as a finish (Slip Graphite or equivalent). Very high temperature and durable according to them, easy to touch up and authentic cast iron look.Then of course others swear by POR-15 High temp or Eastwood or VHT.What has everybody here used?Jim