For BTS the only thing we need for the next 6 months is 100 TPS and a stable / reliable set of witnesses.
For our test networks we can continue to push the limits, but that will have to be done with high quality computers connected to high-bandwidth internet, potentially with very low latency nodes.
At 1000 TPS the bandwidth requirement of the nodes is already near 2 MB per second (assuming the producer broadcasts it to 8 peers and each block is 333KB). Even at 1MB / sec bandwidth, the minimum latency for a block to TRANSFER from the producer to the first peer is 0.5 seconds. If the producer is dividing their bandwidth 8 ways then it will require either 4 seconds or 8MB /sec bandwidth just for the blocks. The actual bandwidth requirements are double that because transactions are sent separately.
In other words, until we rework the protocol to avoid rebroadcasting transactions when we broadcast blocks any peer that is unable to sustain those kinds of data rates will be a problem.
Also, the networking code currently uses more CPU than the blockchain validating code. Fortunately it runs in its own thread. Those running on a single core VPS with 1 GB of ram will not be able to keep up. Those running on a home PC will also not be able to keep up.