I just read a short blurb about efb batteries on an optima battery site. My take from it was they are a cheaper alternative to agm batteries and may be ideal for auto/start vehicles as they perform better than standard flooded batteries.
Pretty much any replacement standard flooded battery will be better than the stock Mirage battery, even compared to a new one. The oem battery is rated for 350 or 450 cca while the one's I've been installing show 640cca(iirc) and every new one I've tested performed better than the rating.
These cars don't have much for parasitic power drains. A few weeks ago I started a car that hasn't moved since last fall. I was pretty shocked.
I service a newish Lexus once in a while, the elderly owner hates it cause the batteries(2) die if it isn't driven weekly.
So I really don't see the need to buy an expensive battery for a Mirage. I'd consider a fancy battery if you drive around like you have auto start/stop then yeah, maybe buy the fancy battery as a regular flooded might not live a long life by doing that.
It's your money though. Some people buy a cheap car then throw and expensive stereo or coil over's and fancy wheels. Everyone's different. I'm just a cheap basturd that drives a cheap car mainly so I can afford to blow money on other crap.
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View my fuel log 2014 Mirage SE wussie cvt edition. 1.2 automatic: 37.7 mpg (US) ... 16.0 km/L ... 6.2 L/100 km ... 45.3 mpg (Imp)