am i going to break my driveline?

You should think about going to 31 or 33 spline axles, a heavy duty posi unit or rebuild the traction lock which wouldn't last as long but cheaper for the kit, about $50.00, and heavy duty upper and lower control arms, and eventually a upgraded T-5, TKO, or C-4 racing automatic.
For now , if you are easy on it, keep your rpms low when you launch, and don't run slicks, you should be ok.
It's all how hard you are on it.
I have GT-40 crate in my 93 GT Mustang with no power adder, 345hp at the flywheel. I launch at 4000rpms with Hoosier Quick Time Pros and run 13.3.
Here's my set-up below.
Good luck!
1993 GT Mustang / Ford Racing GT-40 Crate Motor B-303 Cam / 24 lb. Injectors / Stock Ignition / MSD EFI Blaster Coil / Edelbrock 5.0 Upper and Lower Intake with BBK Phelonic Spacer / Professional Products 70mm Throttle Body / C&L C.A.I. w/76mm MAF / Stock Air Box w/K&N Panel Filter / Holley Adjustable Fuel Pressure Regulator / Electric Fan / BBK Underdrive Pulley's / A.C. Removed / BBK Short Headers / Flowmaster Exhaust / Tremec T-5Z / B&M Short Throw Shifter / Alum. Driveshaft / 3.73 Gears / Eaton H.D. Posi / Moser 31 Spline Axles/ Subframe Connectors / Line Lock / Driveshaft Loop / B&M Short Throw Shifter / Racing Upper and Lower Control Arms / Lakewood Adjustable Drag Shocks/ Holley 190 lph Fuel Pump /