Like ThreeBeans said, Britax isn't best The best seat has to fit your car correctly, your child correctly and you need to be able to use it correctly, EVERY time. All seats must meet the same federal requirements. Once we know more info about your child and budget, we can help you!
Ditto the others -- there is no "best" carseat -- they all meet the same frontal federal crash test safety standards (although Britax & a few others do also perform side impact testing + more reliably issue recalls before an actual injury). The "best" carseat fits the child, fits the vehicle & is always used correctly according to both manuals (carseat as well as vehicle).
Britax seats do fit the Corolla quite well, but if it's out of your budget then there are other options....
What is kiddo's age/weight/height?
Will kiddo ride in other vehicles often?
What are the years/makes/models?
Do you travel frequently?
What is your maximum budget?
Sorry this car seat is for a 5 month old who is just about to outgrow the infant seat and we have another son in a booster ...both dh and I are tall so the seats have to go far back...and we have tried the Britax and it is just not comfortable and very cramped..it is a 2003 corolla .....it will be for this car only .....
I had the same problem with my car (same as yours but older). we took it to babies-r-us because everyone kept telling us it would all fit, even the techs there at the store. so, i made them show me. they were surprised to learn it did not fit as all had thought. so we tried every single combo available from the store and were there hours in 100 degree plus i may add. Sadly enough we are still in the same boat and are looking at newer vehicles. but with yours being a different year you could try the same thing and maybe find something that does work. good luck to you.