Merry Christmas Everyone!!!

For Christmas today my fiancé bought me a brand new 1/16 Greg Adler 4x4 Slash!!!

OK guys! I have been out of the RC Car World for about 8 years so I need some help modifying my car... I put it together today and already had it running! I love it and I am looking to get it moving faster and maybe put larget and thicker tires on it!
This is where I need help! I understand I could put a largest motor in the car but I need information on if I up grade one part of the car what will need upgrading next? I don’t want to over heat or fry anything.

My Slash 4x4 is equipped with an XL-2.5 ESC & Titan 12T 550 Motor

If I could get a list of maybe 5 most needed MODS for my 4x4 Slash that would be great!
(This will NOT be used for racing. I will be using it at my local park on all terrain such as grass concrete and dirt)