What does hopups do to a car... More tunablility? Yes. More durable? Maybe. Faster? Maybe, maybe not. Hopups that will make your car accerlerate faster is lightened drivetrain/clutch, lightened overall weight, even that is hard to tell. Maybe an optional rear bulkhead with vertical ballstud can enhance tunability, resulting in faster corner speed. In ultra high bite track, a stiffer chassis will have an advantage. You get the picture. However, the drawback about aluminum part is everytime you replace a plastic part with an aluminum part, you car gets heavier.
As far as durability of aluminum hopup goes, as a racer I push the envelope on speed and try to achieve lower laptime with each lap. With that, you take risk, you go into corner harder, you brake later, you run tighter. To do that, you will make some error and crash the car, that is part of pushing the envelope, testing the boundries and going fast. To me, if I have to spend $30 to buy 2 hopups, the car crashes, it bends, I'll have to spend $30 again to buy a 2nd round of hopups, vs I can spend $10 on a tree of plastic parts and can replace sevral broken parts. It might not be exact figures, but you get the idea. My bag is packed with replacement parts, 2 of everything. I don't think I would want to afford spare hopup parts, it'll get expensive very quickly.
The optional items on my car is alu middle bearing block because the bearings sit a lot further than the stock block to distribute torque more evenly. Optional rear bulkhead because I want to have one more set of screws to mount my rear tower on for durability, plus the tunability of 3 camber positions and vertical ballstuds capability. Ti layshaft and tight bevel shaft for light weight. Optional steel first gear pinions for durability. VSW007 cause we all know what it does. I'm not running other hopups, unless you count all the tuning aids.... sway, gears, pinions and springs. And I don't think my car will not be as competitive as your Ultimate/X version. If I lose to a U/X version RRR, it's not because of my car lack of hopups, it's because of driver, motor, setup, or just plain old bad day at the track. I hate to have a new guy comes on a forum and think hopups will make a car faster. I used to be Treasurer, VP of a club, we even hosted Nats a couple years back. I see new guys getting into hobbies all the time, the one thing I always tell them is don't get sucked into hopups, learn to go fast in a stock car first. When you become fast and when you know you have exhausted the potential of a stock chassis, then look at hopups that give you more tunability.
It's cool that you dedicate a website for RRR info, adding a section about different setups would be a cool thing to have, just so guys could see how everyone is running their car. I understand you feel the hopups you've chosen will give an advantage, that's cool. And I feel my car is fully capable, not be able to qualify in A or B at a national recognized event would be down to my driving, setup, or motor, not because my car lack of hopups.
Sorry for the long post.
Dom