We're talking the original bent frame Xcell 30 here!!

The frame sides were way too thin, way too close together and way too much distance between the main shaft bearings (which are only an inch apart) and the eng. mount. Just grab it by the top and bottom of the frame give it a twist.
If the frame was so rigid, why did they offer a thicker replacement frame later? Sure, it was a little stiffer, but still flexed and still cracked. The problem wasn't solved until the stacked frame version came out.
Hell, even if you set the thing down soft, you'll here the gear whine change because the frame flex's under it's own weight!!

The stock plastic servo tray flex's side to side with un-loaded control inputs because the only mounts were narrow spaced screws at the very back. This is only fixed by bracing the front to the lower frame; another 'upgrade'.
The front tail drive is a real engineering marvel; a bevel gear (with lots of side loading) on one end of an undersized aluminum shaft that's supported by two narrow spaced bearings at the other end of the shaft!! The soft shaft bends, the bearings wear into the shaft or the bearings fail because of the load leverage on them, the gear strips and loss of tail. This was only fixed with a third bearing supporting the gear end of the shaft. You guessed it, another upgrade.
Now, add a small diameter boom with only one support and a wire drive. I'm sorry Steve, but rigid is the last thing that I would call this design.
Maybe a stacked frame version with these upgrades (or should we say 'fixes') the push-pull setups, twin boom supports, tube drive, pusher or twin tail, uni ball start and all the other upgrades available would be a strong, reliable machine. But, to compare a stock, original Xcell 30 to any new 30 size on the market today is a laugh!

Kirk