1. yes
2. wiseco are good pistions, just do three heat cycles before you ride the bike.
3. dont take it to the shop, learn to do it yourself, the money you will save will mean you can do it more often (a good thing). take your time and pay attention to the arrow onthe piston (pointing to the exhaust port) and also the circlips, make sure the click when they seat.
4. a full wiseco top end and gaskets is arounf $120, before you order you need to figure which size piston to buy, there should be a letter stamped on the cylinder that corresponds to the size. if the bike has got some hours you might want to go to the next size bigger piston.