na no need to do pistons if you dont wont to spend the money. im not sure on prices but i was looking at heads and cam work i im sure the guy was gona charge me $3000 but thats porting head and replacing valve springs and bigger valves all the good stuff drive in and drive out. i would get extractors and a good twin system to. thats what im looking at doing to my 5L i would go with the timing chain to.
Totally depends on the cam. Go big enough and you'll need more compression. Hell the V6 really needs more compression as standard. Increasing the overlap is only going to reduce the dynamic compression.
So basically, good chance you're not going to achieve much with a cam unless you do your home work. Judging by that post, you haven't. So have fun!
You dont need to worry about doing anything else to the engine if your just going a bit higher spec than the standard cam.And you dont need a big cam on a daily driven car anyway. It will just make it a dog to drive.Just make sure you get new lifters as well as the cam or the old lifters will chop out the new cam lobes in no time.Both the lifters and the cam lobes wear in to match eachother basically.I know a couple of blokes who have bigger spec cams fitted to V6's and they run really well.One of them Ive been in a few times now,and it goes excellent compared to when it was standard,he's only got extractors and exhaust fitted besiders the cam.Ive seen it beat a few standard V8,s off the line.It goes good for a N/A six.Lots of low down punch.