You need 12 volts for decent sound. If you get an amp and use an inverter to boost the voltage to 12 it will sound good. There is nothing wrong with those 123 cards. They do static sounds as good as any card out there and they only cost $18 One of those hooked up to a BARC will give you a great cannon sound hit sound and death sound. All you will be missing is the engine sound.

Re Slot cars.

Both Scalextrix and Carrera do 1/43 scale, Many aimed at kids though and you have to be a builder if you want classic detailed cars. The smaller size means a better Scenery to track ratio, and as I am an old Model railroader I want a race track that looks like a scale race track in pictures. I want room for run off areas, pit lane etc.

1/32 is the most popular and that is where the technology of these things is focused. In 1/43 I have to do a lot of my own electronics to mimic what is happening in 1/32. Honestly I have been spending a lot of hobby time on these cars lately only tanking when I have orders to get out the door.

Tanker 10

I have a lot of slot cars. I still have a collection of 1/24 scale Cox cars with the Mag chassis's from the 60's and a whole bunch of 1/32 scale cars. Before I got into tanks I has a routed wood 3 lane 1/24 scale track. I was into slot cars big time and have been since I was a kind in the mid 60's. I needed room in the basement and I got rid of that track. I have since reclaimed some space so the slot cars are getting another shot. I am enjoying 1/43 scale because it forces you to scratch build cars. I am on a mission to build every model of 1/24 scale Cox slot car and do it in 1/43 scale. I am sure you can appreciate how far slots cars have come. The detail on all of the releases now are unbelievable. They are truly scale models that move now. So much more then the old days of Eldon and Strombecker.