Ahh, the Boomerang *childhood memories flooding back*, what a great car, & another that was always on my wish list as I gazed into the local RC shop's window when I were a lad.
Have a look
here for a detailed review. According to the linked site, the Boomerang was base on the Hotshot, but with a few upgrades. It certainly looks very similar to the Hotshot around the suspension arms, so you may find that the re-released Hotshot still uses the same parts, which are now becoming available again. Here's a good site with plenty of info, you might find useful:
Tamiya Club.
My Hotshot is one of the new re-released ones with an ESC. Took it out to the local BMX track yesterday for the first time & it was excellent! I have noticed since building it though that I've got one of the front tyres on the wrong way round.