It depends on what you want to do, I try to convince people to spend $10,000 off the bat if they want to do a turbo car.
You can definitly do it for less, no question about it. I try not to simply because there is no point unless you are 100% satisfied.
What is spending $5000 if your not happy with the final product. Waisted money.
If you get into building a motor then it can cost as much for the motor by itself.
To get an idea of what I put into my motor.... not at all a normal build.
Headwork was done by a guy with a bunch of land speed records in cali. Labor was $1800 Parts $1000
Block was done at ERL. Milled out aluminum sleves and fit cast iron sleves (displacement to 2.0), line bored crank, assembled fully balanced. Labor I think was close to $1400. Parts were roughly $2000
Manifolds, fuel parts, bolts, studs, gaskets, mounts, bolt ons.... $2700 easy.
Turbo $1200
Computer to make it work $1800
.... that doesnt include the stock motor at $4000, putting the motor together, tuning expenses, or labor finishing the car. Also leaves out the numourus hours involved makeing all the parts work right together.
Security is always an issue, I used to be sponsored so they installed the $3000 alarm system for free. =] It calls the police on its own and cannot be disarmed short of blowing the car up and even then the shrapnel would make noise
It also has an undisclosable feature that would send a would be thief strait to the emergency room.
True story, was at the mall, someone broke a window of the suv next to me to jack the system.... My alarm went off due to the glass break and saved his truck. Hows that for lucky.