1. How do I remove the space before each new paragraph? Or just a sentence?
2. Then I would suggest that the search array and the replace array should be next to each other, then it will be quicker to see what is going where.
Maybe even have an array with keys and values, then we could go:
$text = preg_replace(array_keys($this->replace), array_values($this->replace), $text);
That could be easier to read.