Power regenerators *MAY* dramatically improve your sources and pre, depending on how bad your AC quality is. None will be able to handle the Levinson amp. You could definitely consider an AC filter for it though (try before you buy!).
Dedicated AC lines are great, but you have to be willing to rip up your walls.
The Thiels are excellent speakers, but I bet you could improve them with a few crossover modifications. Not changing topologies, just part for part component swaps. Made a very big difference in my speakers. Of course, this assumes you (or a technician) can access the crossovers.
Acoustical treatment can yield very satisfying price/performance benefits, possibly the best. Many commercial options out there and they are very easy to DIY.
Dedicated AC lines are great, but you have to be willing to rip up your walls.
The Thiels are excellent speakers, but I bet you could improve them with a few crossover modifications. Not changing topologies, just part for part component swaps. Made a very big difference in my speakers. Of course, this assumes you (or a technician) can access the crossovers.
Acoustical treatment can yield very satisfying price/performance benefits, possibly the best. Many commercial options out there and they are very easy to DIY.