They are Integy piggybacks. The photos show the Integy springs fitted which are waaaaaay soft. Had to put so much preload on that the damping advantage of the piggy back would have been lost. I have since fitted the standard savage black springs which are much better. The engine is the standard .25 HPI with a Nova racing head which at $39.99 US was real cheap imho. I idled a few tanks thu at run-in and whilst the temp at the block was 204-215 I could hold my finger on the top of the head and not have to take it away. Efficient cooling me thinks! The antenna is just there to keep it out of the way while I took pics.