I don't know what model the H7 "sport" is or which 3-port engine you're talking about,
they don't sell that version over here.

But I have both the "H7 Pro" and the regular (Original I thought) "H7 RTR" version which came with the 4-port, it was a fine engine to begin with.

The newer version, Like Keith Says, have some better features, but any version, Pro, RTR, PBS RTR ,PCR Pro are all good Buggies, The 8-port in the new RTR buggies is great

No reason why an 11 year old boy couldn't opperate one safely