your also gonna have to spend about 500$ or more for engine mounts, there is a lot of fab work involved for anything kinda outside of a sr20… still dont know what kind of car your looking at… if your in a 240 upgrade your brakes cheap with 300z calipers, rotors, good pads, then your gonna need to spend about 3k in suspension and stability… plus more labor $$$ unless you do it yourself…tune…so much shit to do
all these upgrades basically go hand in hand
theres not really such thing as a 3-4k build unless you already buy a swapped car with some mods which would end up saving you shit ton of labor money