I havent used a vortec yet, but the only way it would hurt your truck was if it some how desintrigrated into little metal pices and got sucked into your engine. It has no moving parts and is not eletrical, just a pice of metal to swirl the air.
Dont know about the chip. I was reading on another fourm about a chip for the D2 Bosch engine and they said it was great.
First but gone: 91 3 door Disco "White Rhino"
77 Series III 88 ex MoD "Shongololo"
Gone and I miss her: 97 D1 5 speed
04 DII
08 D3 (LR3)