To the OP you do not state what budget you want to put into this?
Which Logitech speaker set were you looking, their are several?
I would say you would be wiser putting as much money into a surround package first and get a fairly decent one for the price. You can always look at adding tactile later. A sub on such relatively basic surround sets will give a limited quality of bass. It will create more rumble than proper full lowdown bass frequencies. It would be worth putting it close to your seat but will be limited and not produce the same level of effect or impact a decent "Aura Pro / Buttkicker" will produce.
Look on places like "Richer Sounds" "Argos" "Asda" and other large supermarket stores.
You will find for instance on Argos the "LG HT554TH" which to me looks much better than some "Logitech" setups and available for £176.
Link Here
Their will be alternatives but just be sure you get one with HDMI input or at least "Optical Input" to get Dolby Digital.
Regards tactile, well the "Aura Pro" is the best value/performance tactile unit on the market. I would say it outperforms the "Buttkicker Gamer" however I believe "greeze" has both incorporated on his rig and can give you more on a comparison.
The "Buttkicker Mini LFE" packs the best punch for its size. These in the UK are available from
Here as an authorised UK dealer. They provide a better performance than the "Gamer Unit" which really was first developed for PC chairs and while it isnt bad it does have a basic performance ability compared to other units.
They will need their own amplifer and source input.
Hope it helps a bit.
Buttkicker do not support stereo tactile.
All their amplifers will only output a single channel input. So with their amplifers you would need a seperate amplifer and Buttkicker for each channel.
A 2.1 configuration is a big jump up over a single tactile experience.
This would require 3x Buttkickers with 3x amplifers operating via the below inputs:
Left
Right
LFE (sub out)
However to do this requires having the surround decoded audio split into individual channels to be amplified. Again something none of the Buttkicker amplifers do. So a surround decoder with a multichannel amplifer (or seperate amplifers) but usually an AV reciever with built in decoding can be used to decode and ouput an amplified channel for individual tactile channel needed.
Really for many users that get into having a more engrossing "tactile experience" than what Buttkicker setups provide will have a surround setup for their speakers and another for their tactile. This can then be further developed with crossovers / equalisers / bass enchancers.
Be warned it's addictive. I've reached a point of having a rather complicated setup combination of 26 channels. This achieved via 3x AV recievers being used for my own upcoming cockpit. Totals = 14 tactile / 5 subwoofers / 7 speakers used throughout my cockpit platform, pedals, seat and wheel support sections.
You can see it 
