I always have problems with my TRP 8.4 CX brakes. They are real beauties, but the springs are crap, the rebuild kits are expensive... and can't get them in EU. I have a spare spring, but nor I and the LBS mechanic couldn't change it! So... the brakes are weak and the modulation isn't the best at the moment.
What's your opinion, experience about Shimano's new mini V brakes? Or... which brakes do you suggest?
What shifters are you running? I assume SRAM since you are using the 8.4s, but let's confirm.
Andras- I have the same setup and have the opposite to report: The brakes are strong, and the modulation is good. I also take the 8.4s apart frequently to clean/lube after a few muddy races. Not sure what to say about the difficulty you are having in disassembling them. I should point out mine are the light-blue, early-production model, and I run Zipp cork pads for my Easton carbon tubulars.
Before you go buying a whole new setup, perhaps consider changing brake pads to find a rim+pad combination that may work better, as well as checking your housing is setup properly and is as compression-less as possible (like Yokozuna or similar)
best of luck