Pains me to have to agree with Mnb on this one, but it seems I must.
Lots of Palkovi's Smith Morra analyses don't stand up to close scrutiny, but to be fair most of the literature on the Smith Morra is dodgy at best. Perhaps this has more to do with the subject matter, than the authors in question.
Eulogy, my advice to you is as follows, pay close attention:
The Smith Morra is a fun practical opening, however it is not fully sound so expect to continue to find insoluble problems. Flawed openings, especially gambits, can't be fixed fully regardless of how many sources you have or how many new ones come on the market.
If you accept that there are some lines against the Morra where you simply will not generate enough comp then you will save yourself a lot of grief and money. Thats a fact.
I have a friend and he's an FM rated about 2260 or so, and all he plays is the Smith Morra, has been for years. He has that book by Janos Flesch, which judging by his games he never bothered to read, he simply goes his own way relying on his tactical ingenuity to guide him and not bothering a hoot whether the books thinks he is better or worse. I think this is the Spirit that many dodgy Gambits should be played in.
Regarding The Siberian trap, its cool if you can pull it off, and I purposely did not give any concrete lines in my answer since you failed to give any concrete lines in your question. I don't think the Siberian line constitutes a refutation, but if it does, that's what ya get for giving away valuable Centre pawns in the Opening.
Centre pawns are valuable assets and deserve or respect, giving them away just puts added pressure on ourselves to come up with 'the only moves' time and again to justify our wrecklessness.
Conclusion: Smith Morra is a good surprise weapon against an unprepared opponent, but these are becoming harder and harder to find in this Database age.
Solution: Put your analytical efforts into Mainline Sicilian positions, or find an Anti Sicilian that doesn't drop a pawn.
TN
Postscript: In my next post I may show some analysis on the Siberian Line if I can dig up the article on it in the now defunct magazine 'Inside Chess'. If memory serves the article indicated there was some hope for White.