Some good advice here, switch to Ace2 based mods where possible. I did this not long ago. Started with
MarUI which is an excellent minimalist UI package to use as a base. Then I selected 90% of my addons from the included Ace package downloader. A handful of mods I couldn't replace with Ace addons so I stuck with my old versions. Now I'm down from 70mb to around 42mb memory usage and still got alot of stuff running.
I found just switching from X-Perl to ag_unitframes + perfectraid alone saved me about 15mb