torque wrench and piston question

Why would anyone trust a multiple-thousand dollar engine build to a $39.99 torque wrench? You spend good money to buy the best parts you can afford to put in the engine, then use a cheapo torque wrench to assemble it? Discount tool vendors are a godsend for certain tools, but why risk your engine to a suspect quality torque wrench. You should never use a torque wrench whose quality or care is suspect. Rent one? Are you kidding? Get your own. Buy one from a reputable tool dealer and take care of it. Keep it zeroed when not in use, and never use it to loosen fasteners! Your torque wrench... Your engine's life may depend on it!