Hi mate the time has come that you want to xl your savage flux. Best upgrade for the hp IMO you have to make a tuff choice the hpi one has everything you need to get it to xled but if you bash hard the tvps will probably bend or if not worse snap they are only 3mm.
basher grade I would say 4mm minimum. Now with the alza kit if you look at my picture on the first page I got a dogbone with it. BUT sorry to say the alza one is not that great. But all the other duff alza supply is second to none. I got the hpi xl nitro dogbone for my savage. And also get the xl motor mount so much better than stock. And also to complete it you will need xl axles which are really easy to get hold of cheap on eBay
EDIT: just edited the post post with list of products used with links