I already read that one, but still thanks.
He has quite some good ideas (and is able to explain them) in the 3Bc4 complex, when he is not discussing weird lines (Grob and somesuch).

BtW the only times I have played the TKD as black was when I played a Traxler (still the Bc5 move), so I am very unfamiliar with all the Ng5 lines.

I dont understand you exactly. I think you are referring to one of the TKD lines, which I have never played.

I am just in an eternal discussion with Mnb in which he argues that Nf6 lines are better than the Bc5 lines in the whole d4-gambits complex. And there I agree with you that I dont like the lines after 1.e4 e5 2.Nf3 Nc6 3.Bc4 Nf6 4.d4 exd4 5.o-o Nxe4 6.Re1 d5 7.Bxd5 Qxd5 8.Nc3 for black for basically the same reason Mnb doesnt like my lines.

Currently I still have to look at the line 1 e4 e5 2 Nf3 Nc6 3 Bc4 Bc5 4 c3 Nf6 5 d4 exd4 6 0-0 Nxe4 7 cxd4 d5 8 dxc5 dxc4 9 Qe2 Qd3.

As I am without my stuff I cant comment on the line you give. So I give my comments a bit later.
The Qxd8+ line is not very good in the sense that my previous comment is 100% applicable. I have looked at that line a lot and it is not very amusing for white.

I have to say I have an entirely different opinion about the resulting positions. I have played all these Italian-related lines with both colours ever since I learned chess. White really doesnt have much of an initiative and constantly has to find the best moves not to lose the initiative. Almost all the resulting positions (in which the pawn hasnt been returned) have the same basic structure, white has some initiative, but it is very difficult to do something with it. For black it is much easier, he just has to find decent spots for his pieces and always has a cop-out by returning the pawn or offering exchanges.
These gambits are excellent at 1600-level where black players often play too passive or too materialistic, but from about 1700 they are just too simplistic. Tactically they are not very complex (unlike say a Max Lange or Muzio) whereas strategically they are very superficial. I am not saying black can autopilot, but I feel they are much easier to play for black once you have avoided the early pitfalls.
We can discuss the merits of Bc5 vs Nf6, but I think we can agree that objectively they are about equal. With in general Nf6 more focussing on counterplay and Bc5 more on neutralising. A bit similar to the Sicilian and Caro-Kann, though much less extreme.

Ok Mnb point this pawngrabber to one variation in which white gets an advantage.

1 e4 e5 2 Nf3 Nc6 3 Bc4 Bc5 4 c3 Nf6 5 d4 exd4
-6 0-0 Nxe4 7 cxd4 d5 8 dxc5 dxc4 imo black is just a pawn up. Not a very usefull one, but after Qxd8+ or Qe2 white doesnt have very much going on as discussed in another thread.
-6 b4 Be7 7 e5 Ne4 and now  8 b5 Na5 9 Bd3 Nxc3 or 8 Qb3 0-0 9 cxd4 Bxb4+
-6 e5 d5 7 Bb5 Ne4 8 cxd4 Bb6 followed by 0-0 and f6.

After 1 e4 e5 2 Nf3 Nc6 3.d4 exd4 4.Bc4 Bc5 white must play 5 c3 to not get an inferior position. There are some sidelines like 5 Ng5, but they are not very dangerous. So basically when you answer 4 .. Bc5 to these Scottish gambits you avoid all their theory and usually get back to your main line Giuoco theory, which is certainly not worse to the TKD for black.

Thanks, MNb, for putting me right on the 5 c3 Nf6 6 b4?! and the 5 …d3?! stuff! As regards the latter, I guess I was thrown off the scent by Glenn Flear mentioning, after 6 b4 Bb6 7 0-0 d6 8 a4 a6, only 9 Qb3, “with the initiative”. I can appreciate 9 Qd3 is really just good for White, even if in practice I suspect things are rather messy (hence Black’s reasonable score?)? Presumably 7 …Nf6 here, transposing to 5 c3 Nf6 6 0-0 d3?! 7 b4 Bb6, can’t help, as all Black has done is commit his KN. I’m sure I myself would simply meet 6 0-0 with 6 …Ne4, but isn’t 6 …dc reasonable too?; NCO gives 7 e5 d5 8 Bb3, unclear.

I’m really fascinated by the question of classification here that MNb points up! The position after 6 0-0 is treated as a Giuoco Piano in BCO 2 (1989), but as a Two Knights in MCO 13 (1990) and in NCO (1999). It’s also classed as a (C56) Two Knights on ChessPublishing, where it’s suggested there’s disagreement over C55/C56 classification, and as a Two Knights also by ChessBase (8), Fritz (6), and indeed almost all the other chess engines I currently have that give ECO codes! So what’s going on here? One might think the classification might have changed in the 1990s, except that Palkovi’s book (if I’ve got the right one) was published in 1998! Can anyone shed any more light on this?

Personally, unless someone persuades me otherwise, I’m reckoning in practice to short-circuit all these admittedly fascinating lines, by meeting 3 d4 ed 4 Bc4 with 4 …Nf6, with a clear transposition to the Two Knights. 5 e5 d5 6 Bb5 Ne4 7 Nd4 Bc5 (or 7 …Bd7) seems like an interesting game for both sides, while 5 …Ne4 and 5 …Ng4 look OK too.

And http://correspondencechess.com/campbell/hard/h990726.htm

and

http://correspondencechess.com/campbell/hard/h990830.htm