One thing you may already be aware of and may have made modifications to ameliorate, is the lack of built-in rigidity in the Chinese 7x14's and the generally questionable state of fit and finish that it arrives in.
These rigidity limitations can constrain the usefulness of a motor upgrade (not much point putting a 4 litre V12 in a mobility scooter!
)
Here's what I have been doing/planning to my Weiss WBL1835 (Amadeal in the UK's AMA714B model, very similar to many 7x14s out there)
Okay, I did getAmadeal to have a 750W (1HP theoretically) brushless motor installed in mine as part of the deal.
I used a combination of a Grizzly manual (fair play to Grizzly, their mini-lathe manuals are very well written) and ArcEuroTrade's pictorial guides to improving the fit and finish and setup for their Seig C3 and SC3 lathes (my WBL1835 is very similar to these lathes) for my initial setup. Here's the link to those guides if you haven't seen them:
A series of projects showing how to modify your machine using some of the products available from Arc Euro Trade Ltd. We hope you find them useful.
www.arceurotrade.co.uk
So, I'm in the process of various optimising modifications. I've already swapped out the ball bearings to angular contact bearings and have added a carriage lock.
I also have a cast iron toolpost rest to replace the compound in the pipeline (currently got a few parts in brass I'm turning that are required by my better and wiser half, so they come first!
) and am going to fill as much of the empty space in the bed as I can with epoxy granite.
Before installing the carriage lock I parted off a piece of 1214L at just under 3/4" but it took a long time and initially I was making dust rather than chips (on reflection I think it was I initially left the RPM at my standard mild steel speed, rather than dropping down as I should have, noticably I started to get a nice hiss and decent chips as I got just over halfway, where obviously, the effective RPM was slower) and made a sound like I was torturing a cow.
The volume of the sound may also have been due to the fact that the lathe is bolted directly to a 1/4" mild steel stand top.
I'm waiting on a local kitchen worktop maker to supply me with a piece of granite offcut that they'll drill the necessary holes in (it's entirely possible I'll end up with my lathe bolted to a rather fetching pink granite lathe stand top!
) that will go in between the mild steel plate and the lathe.
That should provide me with some extra vibration damping and prevent me from being visited by any local animal welfare groups!
It's worthwhile considering doing that.
I also got an upside-down parting tool holder from Eccentric Engineering (already had their tangential tool holder, which is a nice bit of kit) to be used with the lathe running in reverse but I haven't tried that out yet.
Hopefully some of this will be useful.