What to add to get more power is relative to how much you want to spend....and it you are willing to take the engine out of the frame to remove the cylinder head and/or piston/cylinder.
The first thing to address is the muffler....the Harley DYNA muffler works great and is affordable.
Removing the header will allow you to open up the restrictive ring in the exhaust port. DragBikeMike has a thread on a new insert that can increase flow....nobody has made or installed one yet.
The stock carb, air cleaner housing and filter work fine.....they flow enough air for the engine with some modifications - and likely provide better performance than a lot of the restrictive clamp on filters that folks are using. DragBikeMike has a thread on making the stock air filter housing work better. (I installed a 95mmWiseco, Dyna muffler, Stage 1 cam, ported the head....and I ran the stock carb and paper air cleaner and the bike ran very well and had a noticeable power improvement....I now run a large foam filter without the airbox).
Changing the carb can provide better performance - but really isn't necessary until you change several things and start to make more power and require more air flow. The stock carb works well for just an exhaust and cam change.....when you port the head, install a Wiseco, change the cam - then maybe the carb change is needed.
The next step is a cam....it can be changed while the engine is still in the frame.
If you are willing to take the engine out of the frame.....porting the head helps, installing a Wiseco piston with higher compression helps....and you can install the stock 94mm size - or have the cylinder bored to allow you to use a 95/96/97mm piston.
A light flywheel doesn't provide more power - but does allow for faster acceleration as it reduces the inertia required for the engine to turn.
http://suzukisavage.com/cgi-bin/YaBB.pl?num=1504271719/0 And lastly........my opinion on what to do first and what is best is not "gospel" - others may tell you to go about it differently. It really depends on your mechanical aptitude and how handy you are with a checkbook!