New Calais Owner and i got ?s

[s10blazerman4x4]

Just bought an 88 Olds Cutlass Calais 2.5 motor with 128k miles.
Did a search got some ?s.
First can i put the hi flow 2.25" cat and muffler on? Just wondering on sizes.
Full Tuneup should include the following rite: Plugs, Wires, Cap, Rotor, Fuel Filter, Air Filter, Coolant Flush, Fuel Filter.Anything im missing their. Also PCV and any vacuum hoses.
Im going to need to get some tires, check front and rear brakes.
I havent gotten a chance to get a manual yet but how much oil for the beast of a 2.5 lol. I got some map bulbs out inside and a right turn signal bulb inside the cluster out. The guy who sold the car to me is going to inspect it so the rust on it is no issue.
I love the cluster that is in here. I redlined the motor at 6000-6200 RPMS. I love how the cluster is angled up towards you and how bright everything is.
Also all the buttons and switches got chrome around them. Also heat works insane. ANything im missing let me know and any easy or cheap mods to do during the tuneup?

[s10blazerman4x4]

Changed air filter today along with the PCV.
Got a cold start problem where it will either start rough or just crank and nothing.Once warm it runs fine.
Also oil pressure gauge didnt work today till tonight after i swapped in the battery from the truck but that didnt do nothing to the hard start so i put the old car battery in and it seems to work now.

Getting the brake pads and rotors either done tommorow or friday.Whenever i get time. Its going to the mechanic for the tuneup.Im not that nimble to get in their.

Anyone else got the cool vibration shake at 65?