I've owned my BRZ for 35,000 miles now and let me address a couple of your dislikes and maybe stem your concerns. This is in no way meant to be an attack on you.
1. In stock form yes, the car can be underpowered for some people. However even with just minor mods such as headers, exhaust and intake it makes a noticeable difference. With just intake and exhaust alone I made 30 extra horsepower and because the car is so light it definitely is noticeable and makes the car more enjoyable. Yes it's not neck snapping acceleration but if you want that then get a turbo. These cars have been proven to be able to handle 400hp on the stock engine internals with only a clutch upgrade. Other than that a simple set of headers has been proven to get rid of the notorious "torque dip" in the cars NA form.
2. I would not call the transmission sloppy...sloppy makes me think the shifter wobbles all over the place like a 1980's civic. It does not, the transmission is very stiff and does not like cold weather which is a pain. However 95% of problems with the transmission are fixed with two things. A simple fluid swap (most people here use Motul Gear 300 75w-90 Non-LS) and a little time. The transmission brand new is very stiff and requires some break in to get it shifting smoothly. I notice my transmission was noticeably smoother after the first 1,000 miles and after 35,000 miles (with about 33,000 miles on Motul Gear 300) now it is super smooth and I rarely ever miss a shift.
3. This is not normal...mine doesn't do this, ask to drive a different one.
4. Welcome to driving a sports car...the suspension will be stiff. It's not nearly as stiff as some sports cars I have ridden in.
5. The car comes with tires off a Prius stock on purpose for your drifting pleasure. Switch them out with a set of rims and some Max/Extreme Performance Summer Tires and you will have plenty of grip. I have 225/40 R18 Hankook Ventus V12's on my car and they grip like no ones business. I can't even break the tires lose anymore unless I REALLY try.
6. The reliability problems mostly concerned early models in the production line. They have been fixed for the most part and if you grab a 2014/2015 model you should not have any issues. That being said, I have one of the VERY first BRZ's (VIN Number 301) and I have never had an issue.
7. Yep, unfortunately this car is so low to the ground that is unavoidable. I've gotten used to it and I've found it much easier to get out of the car by rotating your legs out first so you're sitting 90 in the seat and then standing up. I am a moderately tall person at 6' tall. Unfortunately it's not as easy for everyone but you get used to it after a while.
Questions
1. As I said before....better tires change the car dramatically. If you want more grip, getting a set of good performance tires is pretty much the best and easiest thing you can do. The car came with Prius tires stock for a reason, to make the car drift happy and easy to drift. If you're more into the road and track portion of this car then swapping the tires out is a must.
2. It's a whole different monster, they best way to describe it is to just drive one. Ask in your regional forums if anyone in your area has a turbocharged version they would let you test. The people here are very friendly and I'm sure you could find someone willing to let you try theirs, or you could go to a local meetup and check them out. Don't know where you are located but there are tons of meetups in Texas!
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