Dude, i can feel your pain as i have experienced the same thing. i had a hyper 7. Its not that bad, i do not think the 7 will slow you down or negatively lower your driving skill. True that a nice buggy may assist you faster. But, they are relatively expensive. Drive your 7 until it cost too much to fix, never upgrade it again. Just like driving your real car, use it till it all jack up and time for something newer..Dont you think so?
Oh yes, they are heavy.. So what!! I think they are still competitive with the others. Skills..Also, when we race, its all about pre-race preparation. Even you have a 1000$ Xray and there is not enought pre-race preparation done, it = to "0".....
Dont give up on the 7, keep practicing with this, learn cornering, jumping...ect ( I assum you are a 1/8 scle beginner)....sorry if i offend you in any shape or form...