Studio 11 was released in 2005, and is obsolete. You really should use a more current version, unless you need to run it on Solaris 8 (which is also obsolete). You don't do yourself any favors by continuing to use software that is obsolete and pretty much unsupported. But I realize that sometimes you don't have a choice.
You can get the current release, Oracle Solaris Studio 12.3, here:
http://www.oracle.com/technetwork/server-storage/solarisstudio/overview/index.html
It requires Solaris 10 or 11, or Oracle Linux 5 or 6, or Red Hat Linux 5 or 6.
To answer your question, the package installer allows you to select the components you want to install. It is rather coarse-grained, so you usually can't pick and choose in detail, but you don't have to install everything. If you install from a tarball, you can delete the parts you don't want, but you might find that you deleted something that is actually needed.
All that said, whether you install all or part of Studio affects the amount of disk space used, but does not affect the use of swap space. The swap space usage depends on the programs that are actually running. If, for example, you are not running a compiler, the fact that the compiler is installed does not affect swap space usage.
Studio 11 was released in 2005, and is obsolete. You really should use a more current version, unless you need to run it on Solaris 8 (which is also obsolete). You don't do yourself any favors by continuing to use software that is obsolete and pretty much unsupported. But I realize that sometimes you don't have a choice.