A nice looking exhaust pipe is always good to look at as long as it is not so obviously over the top. Twin 4 inch on a saxo comes to mind.
A good sound is probably better than going for the biggest one that can be fitted.
Got a 1988 GTE with a few engine mods sat in the garage. Havn't taken it out for a blast for years, needs a few odd jobs doing to it to get it back on the road. Never seem to have the time or money to sort it.