Question: Will installing a lot of different scripts on my server slow it down?
Answer: Yes, if you install many different scripts on your server that you do not use. It will contribute to slowing down your server over a period of time. The resources on your server includes: memory, hard drive, and processing power. Anytime you install a script on your server a part of each crucial resource will no longer be freed.
After a while these resources will have to be allocated to different scripts. If during any 24 hour period any of the scripts need to do any intensive processing function. The scripts will use more memory and processing power. This will result in less visitors to your site being able to load your site fast.