I wanted a 'simple' stereo in my home office to replace my aging Philips CD-960 CDP and FA-50 integrated amp, both of which suffered fatal failures within days of each other (My AR Amp died years before. I still have the AR XA turntable, but lost my vinyl collection.). I 'tried' to recycle/repurpose old Yamaha Surround Sound AVRs & DVD players, along with earlier bookshelf surround speakers - and even a 10" Sony sub. The AVRs had problems - the DVD player ran wild and ruined several CD's - I finally decided it was time to buy new... I put a $500 limit for CDP, stereo receiver, and a decent pair of bookshelf speakers. I wasn't too far off: CDP Onkyo C-7030 ($169); 50 Wpc stereo receiver Onkyo TX-8020 ($159); and two NHT SuperOne 2.1's ($210/pr) - but enjoyed that system for a few months before adding a JBL SUB550P sub - then trying various Klipsch small bookshelf speakers ending in a pair of RB-81ii's - and that first Emotiva amp. My 'bonus' room is littered with older stereo/HT 'relics'.
I wanted a pair of Heresys since first hearing them forty-five years ago. When I became re-interested, they were $1,700/pr - now they are $2,000/pr. After selling my model collection last fall, I could afford one Heresy - or a nice 1977-vintage pair - and more 'goodies'. I elected to buy the vintage Heresys - wow - then the new Emo amp - for it's headphone capability. So, I have a CDP driving an Emotiva amp - which feeds a pair of Heresys - sounds fantastic - without a sub-woofer. I wasted a lot of time and money getting 'here' - but I love my simple stereo. If The Sixes does what you want, you'll come out a lot better than you likely would otherwise by mixing & matching. The best of luck to you - and let us know how you like 'The Sixes'!
Edited(added): As much as I like my RB-81ii's, I've often wished I had bought the next size LF driver smaller (6.5" vs 8") RB-61ii's as they are a bit smaller and lighter, with only 1 Hz lower bottom end and 2 dB higher SPL @ 1W. Both are front-ported, unlike the RP-160M, which makes placement on a bookshelf possible. The RB-61ii has the same drivers as the RP-160M, the same crossover frequency, the same bi-wire capability, frequency response, power capability, etc - yet differ in SPL by 1 dB (The RP-160M is higher!). The RP-160M is slightly larger (The foot!) and heavier (Again, the foot!). I have no 'need' for a pair of RB-61ii's... but, while they are still available from Amazon and Klipsch for $330/pair shipped - i 'want' a pair! It's an illness...