I want to put a powerbond 20% kit on my ba but I've read confusing things such as having the underdrive kit means you may need to change the thermostat or fan speed?.. What's everyone's thoughts..I was gunna buy a weaponx performance coil pack for but now looking at this as my option

i have one on my car, no mods needed, just install and drive

I've seen powerbond kit with the pulleys and the harmonic balancer but I've seen just the harmonic balancer and belt..what's the difference and does it matter ?..cuz I really like this mod but it's all over the joint with people's thoughts and opinions leaves me in the dark a bit