Well done , The extra bits you added look great . Good idea to hide the tow cable end in the hull, they can be a pain to attach to wire or thread sometimes , I did the same thing on the BA T-34 after replacing the molded on cable , great minds think alike
. To stretch out my cable ends , I tended to bury one end under stowage , so I don't need to use 2 on one model , can't really tell from the pics you posted but I assume you did the same thing . IRC that " not exhaust pipe" is something to do with cooling the transmission which is under that part of the nose . Hot air out or maybe cool air in , as its down the side of the tank where it shouldn't suck in dust and dirt