I also have an Equal-i-zer; it is noisy as the steel slides on steel and the only time you can hear this is in low speed tight turns. So, no, your frame isn't bending and you've probably been unnecessarily sensitized by the 2499 thread. Nevertheless I also believe it is worth reinforcing all of the other 7000 lb. class of Sunlines.
The cause of the 2499 failures, other than a weak frame, seems to be the load on the wd bars, and the way they are levered off to the outside, twisting the legs of the A-frame to the inside. I believe TW is the biggest factor in this failure, but the ultimate failure is more likely due to a combination of factors rather than just pure TW all by itself. Here are the risk factors as I see them:
1. TW in the 1000 lb area and certainly above that
2. steep driveways compared to the street and deep gutters
3. parking on rough ground
4. dragging the skid bars (not by itself a risk, but it means the wd bars are being loaded up heavier as the TV and TT twist or pivot in opposite directions)
5. tight steep turns like hairpins or dropping the inside tt wheels into the "ditch" on turns often seen on unimproved country or park roads
Repeatedly doing any of these 5 things, like driving on and off a steep driveway at home, significantly increases the risk. Basically think of it as the fatigue that sets in when a piece of metal, the front cross member, is repeatedly bent. The first couple of times the piece of metal feels just as strong and can be bent straight again. But it is being progressively weakened, and all of a sudden... pop, it's toast. I believe this is why we're not seeing any intermediate bending between my slightly bent one and the other disastrously bent ones. I noticed mine only because of the 2499 thread, but even that slight bend might only have been one more trip away from disaster as the fatigued metal gave way. In fact, posts by some of the other members indicated that their header failed that suddenly in one trip.
So, what should you, and other non-2499 owners of the 7000 lb. class (and maybe the 2363 as well) do?? I'm no engineer, but the ideas of others helps to get the juices flowing. I particularly like the one part of Bobo's solution to replace the battery supports. http://www.sunlineclub.com/forums/ph...ghlight=#15339
This steel just supports the battery and is too light to resist any twisting of the A-frame. I would knock it out and replace it with at least 2" angle iron. This should not be cut square and tack welded like the original supports. It should be cut at a 65 deg angle and fit tightly into the legs of the A-frame so it's not just the welds that resist twisting. This is an elegant solution that will not look aftermarket and it reinforces the bottom of the A-frame, which is the weakest point because of the cut out in the header basically destroying the strength of its lower flange. If you want a plywood battery platform you might have the machine shop also drill the holes on their HD drill press and save yourself some broken bits.
I'm guessing this is all a non-2499 needs. I believe this is a better solution than Lippert's as it places the reinforcement much closer to the wd brackets where the twisting is initiated and that will greatly reduce the stress on the header. And I'll bet you can get it done for not much more than $100. Lippert's solution is certainly adequate too and will also reduce twisting, but it looks like a "repair" and you'll get much better welding quality out in the open on the A-frame. http://www.sunlineclub.com/forums/ph...ghlight=#15028
To sum up, I think the 2499 needs more than Lippert's solution, but it looks adequate for the 2553 and other similar Sunlines. But I think replacing the battery supports is a better way to go and would certainly buy myself that $100 worth of peace of mind if I owned one of these models.