bigger throttles will give you a bigger torque and more hp right over the rev range like 48mm much better than 45
if you are going to do cams ,will need better springs and better valves most likely do the head at the same time .port job etc and cams can clear if you go bigger lift or duration
as you go up in lift and duration your static comp drops ,so you will need a higher comp set of slugs say 13.5 to 1 with deeper valve releifs
the biggest increase would be quads, 2 stage injection and a decent set of pipes that would be around 15 to 20 kws just in that
a cam with a little bit more duration maybe 5 kws with head job maybe 15