Personally I would keep the T5's, they will benefit later mods, if you so choose, better than the T6's. If you want chrome, take them to a chrome shop and get them plated. As for your airbox, yes it's easy to go back to stock and you might PM NYUK and see if he has the airbox and possibly an adapter boot for your single carb. If not, check e-bay, generally you will find the air boxes with a filter adapter ring already installed and maybe a filter if your lucky.