Re: Lower Control Arms
For the front, they are called A arms. Because they are in the shape of an A. There is also no lower or upper. Just an arm as all that is above is the strut mounts.
For the rear, those are control arms and they are differentiated because you have a total of four, two above in relation to the rear end and two below, hence LCA, UCA.
Now since you are talking front, you can get the tubulars with spring perches to utilize the stock MacPherson set up, but truly, in my humble opinion, you will be spending a decent chunk on something that will net you no real geometry improvements. What you will be looking at will be a little bit of weight reduction in front, which will be reduced due to the addition of spring perches, and some rigidity in the new arms. That's about it.