Your Opinion?! PHP4 coding style - Comment and Splitting source code

Hello all. I'm running PHP4 as Apache module under Linux. I would like to know good script coding style. I should not write long comments in code or not? With Zend Cache, comments should not matter. How about w/o Zend Cache? If I want to write long comments, should I get Zend Cache? Or can I ignore the overheads? For example, 50KB of comments for 25KB code - total 75KB script size. (Not considering disk access/load overhead. I would like to know PHP4's overheads) Whether I should split source code so that PHP4 can parse/compile as little code as possible or not. What is the best coding style you suggest? For example, 200KB script containing all code vs. split into several source files and load 100KB on average when it executed. What is your opinion? Thanks in advance. -- Yasuo Ohgaki