When I was a kid, radio control gear cost lots, even toy-grade stuff; the one time I got a toy rc car was therefore quite a letdown: it was a horrible piece of junk.
Now I've got such a tinkertoy again, a big rc car. But this time it's far from toy-grade, and I'm already in the process of modifying it. This is so much fun! giggle
Quite some people use the recently released HPI Wheely King as basis for building rc rock crawlers, because it's got solid axles and four link suspension out of the box, it's not overly pricey and generally quite amenable to modifications (out of the box it's a bit top-heavy and does wheelies too easily).
Mine is second hand off ebay, but hardly used and the original owner already spent a lot of spare change on hopping it up: initially it was an older 2WD version, but the 4WD conversion was done, all the structural plastic (except the axles) was replaced with shiny allow stuff and so on. I still got the original parts, and also a second bigger battery, for not too much money: au$220. Very nice, considering that the best price for a stock new one would have been around to au$300 with shipping from murkia.
So I spent some time today farting around with the suspension, have it climb up the rocky hillside outside my house, making up Tamiya-plug connectors for the charger, retrofitting an onboard charger plug into the remote control housing and so on. Plans for the obligatory wheelbase extension (crawler here we come!) are already being made.
As I said, quite some tinkering fun. I accidentally drove over one of the bearded dragons outside today: there's two that are commonly found around my house, and they are darn hard to see if sitting in the long brushy grass. This time the fellow had to sprint a bit :-)