I got a base Pontiac vibe not too long ago w 155k miles, I did the following to it: replace valve cover gasket, degreased under the valve cover, replace pvc valve, thoroughly clean the throttle bottle, replace the timing tensioner o-ring (common leak), replace all fluids (dex merc for power steering, prestone 10 year for coolant, dropped auto tranny pan, replace filter and used maxlife atf, 5 or 10w30 full syn at 8K OCI) new platinum NGK spark plugs, new air filter, new cabin filter, new brake pads and shoes (rear). I drove it from Los Angeles to Boston, up and down New England and back to Los Angles and it ran perfect, 30+ mpg, cold AC, cruise control good, etc. It has almost 180k miles now. I had an 03 prizm also, with a manual trans and used ac delco manual trans fluid per the users manual and it shifted smooth. I don’t remember how much $ for the fluid but it was not expensive. Congrats and enjoy your new to you matrix