Take pictures of all your gear you are taking, get it all insured and give those pics to your insurance agent.

1) I would air freight ahead and not try to take this gear as personal baggage. Unless you are part of an obvious TV crew or something similar, customs heavies at European airports are currently very suspicious of anything large and electronic in your possession. Freight between the US and main European destinations is a well-oiled process and is not showing any real problems, even under the current conditions.

2) How much of your mains-operated gear has universal input or can be switched to operate on 230V? Air freighting a transformer large enough to power a recording rig can be expensive. It could well be cheaper to buy and freight a UPS that has universal input and 120V output, or, if you can find a suitable one, buy it in Europe and ditch it before returning.

3) I can't comment on your implied US tax question, but airport customs are generally only concerned about the origin and value of the gear and the purpose of shipping it, and not whether or how or in which country you might be paid to operate it.

Good luck with the trip, and be sure to let us know how it turned out!

As label boss ( hybernating, atm) I have collected some experiences about touring and I can recommend on the following:
Try to get the whole tour and entourage officially stamped as cultural exchange at some embassies... In some (only some ) cases you get extra free weight on transports and a little extra fonding.
If touring Germany, be prepared to cope with our beloved GEMA ( equiv. to BIEMA ) and this dreadful institution the Künstlerkasse, which claimes a few % from anybody ( graphic designer to fart artists...) for a artists social fund ( I would translate that so), Those collect money and pay support and pension to affiliated artists of all kinds. They claim that from you, even if you are from the Brasilien Rainforrest and never get a dime out of this. Some promoters and organizers take care of that, others don't.
*GEMA asks money for every gig from the organizer, also if you play only your own songs. Usually, the rate is depending on the square meters of the hall and entry fees. They ask for a play list of the songs, as well, for accounting. You might get about 90 % of the fees payed out after a few months, if you play own songs and if there is finally a working coopration scheme between Biema and Gema ... Some organizers try to ignore the GEMA...only some get away with it. It means extra income to you as composer and texter, but some organizers would not pay GEMA and rather don't invite you, at all, then to pay it...Some even ask the fee from the bands, which I find absolutely reprehensible!

Then: take all proofs of purchase, bills, invoices of the equipment with you, that you still have. Occasionally, customs of some countries get nasty and want to see the origin of the goods and proof of purchase or claim import tax. To get that back when leaving the country again, means lots of paperwork and is complicated, too.
The arts are drowning in paperworks... I know,... and it sucks big time!!!

(*Of course, you must be affiliated to BIEMA or equiv. organisation with your songs, though)

Just trying to get some "electronic" things into and out of Canada was tough enough - going to Europe will be a real challenge.

Make sure everything is on an inventory that you can hand the customs people. They will want to know that what you are taking in is also coming out and that you are not selling it en route. Pictures are always a good thing to have especially if all the pictures have the same background and date taken stamped on them.

I too would send thing ahead BUT I would send them to a specific person or "protected warehouse" that you know will take good care of what you have. Don't send the stuff to a venue since you will have no one responsible to sign for it and it could easily get lost.

If you have to take the stuff with you then I would contact the airlines ahead of time. Tell them what you are doing ask if they have a way to ship your stuff in the same aircraft as freight and not as your baggage - you will pay less. You will have to pick it up at a separate location from your baggage but the cost savings are real.

Make sure you have everything well protected if in rack cases and think about isolated/shock mount cases even though they cost more and are bulkier. Have your name and address on the outside and inside of every piece of freight. I use florescent colored tie wraps to secure the latches so I can see if someone has tampered with the cases before I accept them at the other end. One problem now is that a lot of stuff is being opened en route to see what is really in the cases so this idea may not work considering the circumstances. Have an inventory in the boxes and on your person. Others have really good suggestions and I am not up on the latest tax situation but it maybe a good idea to check out everything IN ADVANCE especially if you are going to work multiple EU countries. There is also the dreaded VAT tax and I am not sure how that applies to services rendered.

As to power. You have already gotten some good advice.

I would think that, depending on where you live, you could go and talk to someone who is a freight forwarder/expediter and they could give you lots of good advice. We used BAX GLOBAL and they seem very knowledgeable. They have been purchased by another company and here is their website [[url=http://[/URL]="http://www.dbschenk…"]DB Schenker USA > Home[/]="http://www.dbschenk…"]DB Schenker USA > Home[/] They seem to be up to date on all the applicable laws and regulations and were GREAT to work with. They also have protected warehouses that you can safely ship to and ONLY you can claim your freight from.

Best of luck and make sure to get all your ducks in order before you leave the US as things can get very confusing very quickly once you are on the other side of the "pond". One additional word of advice. Always be in a good mood when dealing with custom agents and anyone in charge that you have to work with in a foreign county. They are always very professional and in most cases nice but if you try and brow beat them or get uppity they can make your life a living he!!. I speak from experience and you don't want an AR-15 pointed at you for going the wrong way in an unfamiliar airport with signs you cannot translate - believe me.