I`ve got a few around here as well. Happen to have an old Rustler, was my son`s first one. That one though is heavily modified (although still not brushless). Changes out control arms, hinge pins, shocks, gears, wheels, tires, controller, servos, motor, etc. But the biggest part of the `mod` is I went over every little place I could with a Dremel and hollowed it out. Don, you`ll know what I`m talking about.

Where all the bracing is in the chassis, I went around all those areas with a cutting bit and took quite a bit of plastic out. It lightened it up a LOT. The back end tends to want to pass the front quite a bit.
Then of course there is the old E-MAXX from the same era. Some RPM parts on it, different gears, motors, servos, and light shock mods.
The big money pit I have is a full Integy polished Aluminum Revo with a big block. Nothing on that thing is stock but just a few pieces here and there. Last count I had well over $2500 in it, WELL OVER. :blink: It`s more of a show truck than a basher, and it`s HEAVY as crap also..... just don`t like getting it dirty! LOL
Then the evil twin to the show Revo is a carbon fiber chassis one, same big block, but all (long) RPM arms, mods everywhere, pipe, front and rear main shafts, wheel shafts, oversized bearings (hub bearings), really ultra light for a Revo. Custom dyed the RPM pieces in red RIT dye. Wheels, arms, bumpers, even spoiler. They look awesome! Built that one for my son and the first time he drove it he ran it up his shin running about 30MPH and about broke his leg. Parked it... and it`s not been run in years.
Then I`ve got a fairly stock OFNA buggy. Not the fastest thing on the planet, runs closer to the ground than the trucks (which means you need CLEAN dirt to run it), but it`s tough as nails.
Of course I have a pile of OEM controllers then two KO Propo Controllers, an original MARS that was far better than anything OEM and still complicated over a OEM controller, but easy enough to get far better performance than a factor one when it comes to how well you`re RC`s will drive.
Then I invested in an KO Propo EX-10 Helios that takes multiple engineering degrees to program!:wacko: I had to read the manual over a WEEK before I would even consider trying to run one of my trucks with it.
Think I have it set to run 3 of the trucks I have, the two Revo`s, and the OFNA. It`ll hold up to 10 different vehicles. The trick though is you can program quickness of the servos, how linear they are, ABS, launch control, punch, fast turn in vs slow turn in vs slow at first then faster the more they move towards their programed motion etc. Throttle response can be programmed nine ways from Sunday to get that perfect start, yet have maximum speed say 50` out (for instance).
I`ve never got around to programming everything it`ll do, and taking notes on one versus the other... just too much. It`s literally amazing how many parameters the darned thing has. Of course it`ll do lap counting, lap timing and all that. It`s not a `digital` controller though, but it is FM (with quick change modules, and frequency modules as well).
Then there are the piles of custom painted bodies. Some of which have never been used.
Of course no serious RC-er would be caught out without a complete racing kit, parts bin, tons of extra shocks, shock valving, shock oils of ALL thickness, gears, screws, tools, pipes.... went crazy with that stuff back 10 years ago, (and hardly ever used ANY of it). Got another grand there for sure.
Can`t remember the name of it now, but I bought this aluminum jig that I can use to align all four wheels. Mounts to the axle shafts and allows you to set caster, camber, toe, ride height.... you name it. Problem is, the big Revo`s are too big to fit both sides at once!
Too much money spent there for SURE. :redcard: