Hmmm... Not tackled mine yet. It's one of many on the 'To do' list.
Unlike yours, mine actually came with the RX42B. Just another of the mysteries of SCX.
I don't quite understand why so many folks dislike the SCX guides so very much. Can't say I've yet had a problem with them. But each to their own I suppose.
Being such a naturally high centre of gravity, I'd be inclined to sling a little weight under the chassis if club rules will let you get away with it. It's been known to work wonders on occasion.
Embs