This has been talked about a bit here, but let me repeat a couple of standard conclusions –
- adding another spring of the same kind generally does help – it tightens the stick a bit (increases the tension), but what generally happens is that the springs start to screw around each other and overlap… You definitely notice a reduction in tension after a few days but it’s still tighter than a stock stick;
- replace the spring or add onto it with a JLF or Seimitsu spring; you don’t like the JLF-SP so try an LS-32-01 spring;
- the tightest spring you’re going to find is probably at Home Depot. They sell a pack of four springs for $4. Any of the springs in that pack can be used with a JLF or Hori stick shaft. Cut them in half – even the longer, less tense springs – and try them out.
(Do NOT cut the longer, thinner springs in half as they are less tense than the shorter, thicker springs to begin with. Cut those in half, too. If you cut the longer springs in thirds they won’t have enough tension for your sticks.)
I’ve only used the shorter spring after cutting it in half and found it was fine for my purposes. My sticks were way too tight when combining JLF/Hori/or LS-32 springs with the Home Depot spring. My best combinations have been Hori spring and JLF spring, two JLF’s together, or a Home Depot by itself.
(The Hori springs in the FS sticks and Tekken 5 stick are about equivalent to a JLF spring.)
Your mileage (what feels comfortable to you) will vary…
Adding or playing with different spring tensions is the cheapest, easiest stick mod. People talk about modding gates, putting tape or heat-shrink tubing on the stick actuator but I really think you ultimately have to play with the stick with minimal mods. Most of the mods begin to sound like a lot of work for little reward and they don’t seem to give the bang for the buck that a spring mod does.
Anything else you want to know about springs you can find with Search.