Shaking on it doesn’t signal the end of your buying process; paperwork is a natural part of acquiring your new car, secondhand or not. Secure your original certificate of registration, official receipt, transfer of title, motor vehicle clearance, absolute deed of sale, and if it already has a LTO-issued plate, make sure you get hold of that as well.
Also, if the car qualifies for insurance and warranties, you have to have the corresponding endorsements and documents for those too. Have the car’s inspection results and maintenance records within reach as well; you won’t know when you might need them.
Owning a secondhand car might set you back some peace of mind, but out on the road, performance always trumps price!