dont depend on those to crank in cold weather. Reliability to start falls off when you have less cold cranking amps. Keep one for the track but keep your lead acid for daily
I have found that the small batteries work best for daily driven cars in mild climates. Brailles and other dry cells tend to lose charge if the car sits. They have to be cycled often. They do take a charge quickly when discharged, but it is a PITA to throw a charger on every time you don't drive your car for a while.
My Porsche used to go flat all the time did my head in (factory battery) changed it to a Lightweight racing battery was so much lighter and worked much better so go figure I guess
iv e ran a braille for the last four years. running a 17lb. in my mustang. there is a hole in the bottom of the battery tray that i dremmeled out a little to fit the battery in tite then foam and bubblewrap around the baterry. the 17lb. has plenty of cranking power. jegs warrantys them for 3 years also. i got a new one at almost 3 years old. in my mini it was 33lbs lighter than the stock battery!