You said money isn't a problem. If that really true, just go get the OS .18TZ and be done with it. The OS isn't that expensive and its reputation for reliability and power output are great. Whatever engine you get, make sure you get one with a "Standard" crank shaft. You can tell the engine has this because the crank shaft has threads on it. Also, make sure you don't get an engine with a crank designed for a Tmaxx. The crank is threaded but too short for your car. Here is the correct one.
This will bolt directly into your car and work. The only thing I'm still not clear is what exhaust you have right now. The engine I showed you above has a "rear" exhaust on it. You will need an "outlaw" or "turbo" exhaust and header for a .12 block. Like this.
I'm thinking you have a side exhaust setup right now.
You'll also need an air filter and filter oil.