I managed to do it! Decore the foams that is.
I tried to take off the right side foam tip, but I had to put a lot of force into it to get the tip off. Unfortunately the core is still on the nozzle, so I'll need to cut that off with a knife.
I think the left side is going to be treated similarly. I will try to contact DealPerfect or SoundMAGIC and ask for the new tips which hopefully won't fit so tight.
There's also still a chance to split the PL50's. If that happens, what should I do? Ask for replacement, or a refund?
UPDATES: I managed to cut the cores from the foam tips off the nozzle and have already contacted Jack from DealPerfect concerning some new, upgraded, foam tips.
IMPRESSIONS: So far, I really like how these sound. The bass is definitely lower in quantity compared to my Canyon IEM's, but the PL50's treble and mids are way ahead. No competition, especially in the treble region. The downside of the silicone tips is that they sound a lot more neutral compared to the foam tips. The mids are still forward, but I find the foam tips to be more lively and that they give a more layered sound to the music. The silicone tips seem to 'blend' the music more. Comfort (especially with foam tips) is very good, nothing to complain in this area. These are a bit tricky to fit at first because they are so damn small and I have to get used to the over-the-ear wearing. I'm not going to comment on build quality yet, as there is still a risk of splitting them. But that is something time will (or will not) tell.
Overall, I really like these. They will undoubtedly be staying if the housing doesn't split. And maybe I can enjoy them even more if I get a new set of improved foam tips.