What is the cheapest I can build a 1/8 brushless buggy?

[R00ST]

Also...what do these buggies tend to run weight wise after converted? I was hoping to keep the weight down but dont even remember what my last 1/8 buggy weighed. I just need something super durable. I would like a 40-50mph top speed with great acceleration. I miss my old nitro 1/8 buggy as I took it to the skate park and beat the SNOT out of it without breaking a single thing! Unlike my old ss5800 pede that went through 20 bucks in parts every 5 minutes of skate park action!

It would be nice to be able to re-use the MM (buy a new motor) and just sell off the lipo's if there is not a motor that will run decent on 3s or 6s. I could always grab two new 2s (to make 4s), or a 3s and 2s (to make 5s).