There isnt much risk of a backfire unless you kill your engine and keep spraying fuel into the intake. A WOT switch pretty much prevents that and I installed an extra safety feature of a RPM window switch also. Ive hit the fuel to test the system with no problems. Explosions happen with BIG 500hp systems and they kill the engine and it contintues to puddle fuel in the intake and BAM!
Drys kits are nice, just make sure you have plenty of fuel. They both work great.
You can use upto 150hp safely on a stock motor if not more.
Adding heads/cam/exhaust "modding" your car isnt going to make it anymore resistant to N20. The 5.0 bottom end is strong. Retard your timing, regap your plugs, make sure you have a WOT switch, and you have plenty of fuel and you'll have lots of fun with the n20.
Skyler
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-1989 Saleen Mustang #406-
TFS TW Heads, E-303, Edelbrock intake, 70mm TB, 73mm MAF, 24lb injectors, 1 5/8 shorties, Off Road H, 3 Chamber flows, Jaz Race seats, Back seat removed, sub-frames, Roll Cage, and a 80 shot of N20.
12.54@107.4 Motor
1.69 60'