Upgrade to Totem Forest or Monitor Audio GS60?

For rock, prog-rock, techno, electronica, and any other musical style where you want pits of hell deep bass that's accurate, fast and musical, great mids and treble and the ability to move a lot of air, check out Legacy Focus HD.

Strangely enough, Mimberman and I had the exact same upgrade path. I had the Forests for about 6 months and upgraded to Dali Euphonia MS-4's.

I, like you, listen mostly to indie rock and heavily produced rock recordings. I truly enjoyed the forests, but one issue I had in my system was that the sibilance on some records (singers pronouncing the letter "s") actually got too hot for me. Once I started hearing it I just could not get around it.

The voicing of the Dali's is such that I have gotten rid of the sibilance problem, but without losing the detail, speed and transparency I enjoyed so much with the totems. Also, even though one of the Forest's strong suits is bass, especially for their size, moving to the larger Dali's has confirmed that there is no replacement for displacement. Bigger drivers and bigger cabinets are going to move more air.

The Forest is a fine speaker, but like Mimberman, I suggest you give serious consideration to Dali Helicon 400 MkII. JM Lab does make a great rock speaker as well. I auditioned the 1027's a while back and really, really liked them.

The slippery slope here is that upgrading to the kinds of speakers being mentioned (JM Lab 1027 BEs and Dali Helikons) may expose upstream weaknesses. I haven't listened to your Arcam amp, but am very familiar with others in by Arcam. I've found Arcam to be very pleasant sounding, but not the last word in dynamic reproduction, which given your taste in music, may be an issue. A two driver setup like the Forests isn't going to move the amount of air as most of the other speakers being mentioned, true, but you're still dependent on your amps ability to power whatever you choose. At 100 wpc into 8 ohms the Arcam is capable of driving a bigger speaker (truth be told, I found the Forests power hungry) but you may find you're still lacking that final bit of depth and size.