Whether the loss of those ARP 2600 loudspeakers is aesthetically acceptable or not, is up to you. The truth is that the upgrades offered by Phil Cirocco are technically and musically outstanding.
Since the modifications have to be done in the USA (at CMS), customers from Europe / Asia / … need to send their ARP 2600 overseas. Which is not cheap, but still nothing compared to the 5000+ USD that a full-blown CMS upgrade costs. In other words: Classic vintage analog synthesizers are a costly affair in all respects.
Be that as it may: The modifications are worth the money. I only wonder why the fourth VCO is on the right (!) side and the second VCF on the left (!) side. But surely there are technical reasons why Phil Cirocco opted for this arrangement.
Some pictures of the modded ARP 2600: