You have great stats for all but a handful of majors at UIUC. I would say 1530 SAT plus at least maintaining your current GPA above makes ACES/HS majors nearly a safety, a very good chance for most LAS majors (other than some selective ones like CS+x) and a very good chance at many engineering and business majors. The exceptions would include Bioengineering, Computer Science and maybe Mechanical Engineering that may still be borderline and should be considered as reach majors. If one of those interests you, you could always list something like Engineering (Bioengineering) as your first choice and something like LAS (Biology, Biochemistry, Molecular/Cellular Bio or Chemical/Biomolecular Engieering) as your second choice major on the application. Or whatever interests you of course, those are just examples.
UIUC doesn’t accept SAT2 subject tests directly, but you could list those results on the achievements section of the application. I would not even bother unless another school suggests them or you are trying to get into a very selective major like Bioengineering where anything relevant you can add to extracurriculars and academics may help.