it's been asked already amigo so my curiousity is peaked also, is this your first engine?

if so, then welcome to jet portion of the hobby and good on ya for asking questions to some of your concerns. [sm=thumbup.gif]

if it's not your first engine then i'll only mention (in my experience despite being a rep) they are good lil motors but remember each manufacturer has their own quirks or unique sound. line 'em up, AMT, JetCat, Jet Central, Wren, JetJoe, Kingtech, PST, Evojet, Hawk, Frank, Merlin etc. etc. they all accelerate differently, some faster, some slower but by and large they are all very similar and produce their own distinctive sound. (I'll use Jet Central as my example because I could always tell when my buddy was firing his up during startup or during takeoff roll, very unique initial acceleration) same goes for Evojet during startup

IMO, the video doesn't show anything out of the ordinary amigo. stuff it in your jet and enjoy as others have already stated.