Hi I have altered the rear exhausts so hopefully they will smoke correctly . Its not the way I wanted as it has a pipe out side of the exhaust unit were the smoke will feed into the exhaust . But it will be covered . I just sealed the exhausrt unit removed the moulded exhaust pipes and replaced them with a piece of bent styrene pipe . I drilled a hole into the bottom two out side corners of the exhaust unit for these pipes to fit into. The exhasust unit was glued and sealed to the rear pannel . I then drilled two holes into the top and put two halfs of a pipe then Im going to put a top piece on . The smoke pipes will feed through the normal holes into the exhaust unit and hopefully out of the exhaust pipes . However I havent got a RX18 board so I cant test it just yet . But its not a big job to alter it.
metal Asiatam suspension , metal sprockets (thanks Dave

) and metal return rollers (thanks Steve

).

Inside view of modded exhausts , note the tops of the little half pipes still needs caping. I might add some sort of angle piece in the top so the smoke goes downwards better ?

outside view of exhaust pipes .
Andy