To Do or Not to Do. That is the Question.

Running FireBug in Firefox, as a tool ......

[Propools]

Running FireBug in Firefox, as a tool
I’ve got two questions on the suggestions and if doing them will negatively or positively effect the SERP.

Currently page speed is 77 / 100.

The two suggestions which I would like to get some feedback on are:

• Enable Compression -
  Compressing the following resources with gzip could reduce their transfer size
  
• Leverage Browser Caching -
  How do I do that?

[phranque]

assuming Apache 2.x in your case, to enable compression, use Apache Module mod_deflate:
http://httpd.apache.org/docs/2.0/mod/mod_deflate.html [httpd.apache.org]

to leverage caching you need to send Cache-Control and perhaps Expires headers with your responses and then respond appropriately to the If-Modified-Since [w3.org] header provided with subsequent requests.
"appropriately" in this case means if nothing has changed, instead of serving the resource with a 200 OK status code, you send a 304 Not Modified [w3.org] response.
more information in Cache control in .htaccess:
http://www.webmasterworld.com/apache/4108533.htm [webmasterworld.com]