Doesn't the impedance curve of the Forest make it unsuitable for tube amps. There's a fairly wide high peak centered around 2K.In comparison with the frequency response that would result if the speaker were driven by a solid state amp having negligibly small output impedance, with most tube amps there will be an increased emphasis of frequencies in the region of that peak. But given that the speaker's impedance, as shown here, does not go much below 8 ohms at any frequency, the difference will not be major with tube amps having output impedances that are typical of those in the power range likely to be considered for use with these speakers. I'd be much more concerned if the speaker had an impedance variation, as a function of frequency, between say 4 ohms and that peak.
For example, with a tube amp having an output impedance of 2 ohms, corresponding to a damping factor of 4, the frequency response rise in the area of that impedance peak, due to the interaction of amplifier output impedance and the variation of speaker impedance as a function of frequency, would be less than 2 db.
On the other hand, it seems possible that the distortion performance of some tube amps will be less than ideal working into that kind of impedance peak, because of the difference between that peak impedance and the impedance the output tap of the amplifier is designed to work into. It also seems possible that the distortion performance of a marginally powered solid state amp will degrade somewhat at frequencies in the area of that peak, because of its reduced ability to deliver power into such a high impedance.
So there is some guesswork involved. Personally, though, given the cost constraint and the preference for an integrated amp, my instinct would be to go solid state. Some good recommendations appear to have been offered above.
Regards,
-- Al