I would not add to the filtering until there are real signs that the current filter is not up to the job. I keep in mind what the filter is meant to do for me. Mechanical to keep the water looking clean, bio to process ammonia, are the two I need most. I suspect your filter is doing all that is required. So for flow, it gets down to dropping $80+ to get one spot moving better or $20 to 50 to get the same. I go for the powerhead over the filter for movement, if needed. They are comparativley cheap, versatile and certainly far less maintenance. You can hide them behind rocks or wood far easier than a couple filter tubes.
If money is not too tight, try going with one of the Koralia line for great long term value. Far better mounting options with less noise and I also find the design of the cage makes them far less nuisance from clogging when leaf debris gets in them.