My 2002 Prius is getting to the age where I am worried about the 12 volt "motorcycle" size battery failing. A Toyota replacement I am told is $190 and there may also be a $50 charge for a kit since the replacement battery is bigger and better and won't fit and/or connect without the kit.

Doing some Google research I came across a battery from WestCo made for Mazda Miata and Prius that cost less than $100 including shipping and a kit for $25 (about half of Toyota... no surprise). Any body have experiance with this?