Fair enough. However, I found the 200fps stock on my AEP to be low enough that folk genuinely weren't feeling it, and I understand the R4 is about the same as stock. If you're confident with gearboxes, either an Eagle6 or Laylax spring will give you that extra bit of sting, and it's about the cheapest mod you can do.
If you're set up for soldering then the best bang for the buck is wiring for lipo though. Heck, lipo batteries are cheaper than the stock nihms.
Is the accuracy on your Well not great then? How's the hop rubber looking?