This is not really a perl question, but the answer is:

"tar x..f tarfile" will unpack the contents of the named tar file in the current working directory -- period. Where the tar file contents are placed after tar extracts them is fully and only dependent on what the current working directory is when the tar command is executed. (The actual path/filename of the tar file given on the command line can be anything/anywhere, so long as the shell running the tar command can locate that path and file, but the "cwd" will be where the contents end up.)

So, controlling the location of unpacked contents involves the "cd" command (or the "chdir" function, if unpacking a tar file from within a perl script).