Sound Replacer is the best way that I've found to replace drum sounds. Once you get the hang of the settings it's usually fairly accurate and pretty quick. There are other methods that I've tried, like using a drum module with trigger inputs. Both methods will need minor tweaking. With SR, I usually create a new track with the replacement sound, then solo the original drum track with the replacement track to make sure that they're rock solid and make adjustments as needed.
When doubling the original sound with another using sound replacer, I usually get the best results by aligning the start of the waveform, not the peaks. YMMV.