hiya mate
aye it can be expensive, but for an FG Monster there are some essential hop-ups you wanna do asap to make it bashable..
Alloy hubs (Defo on the front & if funds allow on the rear too) the stock front ones are weak & you will be replacing them many times due to stripping!
Alloy Rear upper A-Arms
Alloy Rear Shock mount
Steel gears (Pinion & Spur)
Alloy Radio Tray / Servo Horns
Outerwears for pullstart & Air Filter
That lot will prob set you back a further £150-200. But well worth it as you wont have to worry so much about parts breaking when your out
To be honest ive had my FG MB Pro for about 5-6 years now, up until last year it was pretty much stock except for steel gears & alloy servo horns! yup i did bash it & yup it's had a fair few bumps! ...but last year a few things started to give.. I bought 1 alloy hop-up..follwed by another & then another.
Best thing to do, if a stock part breaks, replace with alloy

...downside to this is it don't help when it brakes when your out! ..so i just went ahead & started hopping up wit alloy with more important parts 1st