Thanks for posting this thread! Google just sent me here and I read it through from page 1.
I have a 2021 Forte5 GT 6MT that I initially leased for 3 years in Jan 2021, and subsequently bought out this past January. I had a habit of flipping cars (usually at a loss) every 6 months to a year, so a 3-year lease seemed like a good option to keep me in a car for longer, but have the option to move on in three years if I wasn't happy. Fortunately, I'm still happy with it!
The 6MT GTs may be uncommon in the US, but they're downright rare in Canada. The manual transmission was a 1-year-only option (2021) here, and only on the hatchback (which the US didn't get). There were about 160 total brought to Canada. My 128i was costing me more per month in maintenance and repairs than the monthly lease payment on this, so it made sense for me to ditch the BMW frustration and get the Kia. This fortunately occurred at a time when the 6MT was new and available.
I'm currently about 3.5 years in and just about at 55,000kms (34,000 miles). The car has not had any major issues, and just a few small ones. I was searching for info as this morning I depressed the clutch, heard a twang, and felt something land on my foot - looks like the clutch pedal return spring broke. The pedal still functions fine but seems to have a bit more play at the top end - I'll take it in to get replaced, which I expect will be under warranty.
I've not experienced any seat wear issues like you have, but I have worn away a bit of the leather on the steering wheel where I often hold it. I also get a seat squeak sometimes when depressing the clutch pedal, but it usually just seems to be in the winter. I assumed it was cold materials rubbing against each other, but I'll look under my seat to see if it has done the same yours did. Also dealing with a persistent rubbing-type of rattle which seems to be coming from the back of the headliner just before the hatch...driving me nuts and I'm going to have the dealer check for that as well.
I've been running 91 octane from new, and have not experienced any of the throttle issues you've reported. I do also clearly notice the lack of boost when the engine is cold, and power dropping off hugely after 5500-6000rpm. I have had a very difficult time shifting smoothly since day 1 - could very well be user error, but other manual cars I've had in the past have not been this way. Going to try driving with TCS off later to see if that helps as was suggested, but I've been chalking it up to terrible throttle mapping. Seems 80% of the throttle is mapped to the first 20% of travel, which makes feathering difficult, and I also find a very abrupt difference between throttle-on and throttle-off. Wondering if a tune could help with that.
Fuelly tells me I've averaged 29.77 mpg, and that includes me warming it up for 5-10 minutes every morning in the winter, because I'm a wimp that hates the cold.
My last provincial safety inspection in Jan showed the front brakes nearing replacement time, which surprised me. I have heard a very faint, very high-pitched noise on occasion from new, so I'm wondering if mine are dragging a bit too.
Fortunately, my dealer is great. I have the impression that Canadian dealers are just more helpful than US dealers in general, but I'm also well aware I get special treatment - I worked there for over 5 years, nearly 3 as sales manager, and left on good terms. Everyone there always seems happy to help.
Anyway, thanks for all the info and updates!