trade my Z for a bmw 135i?

ssmoked

I actually had the pleasure to drive an 135i convertible for a week. The steering is definitely firmer and more predictable than the 370. I had more confidence at higher corner speeds than the 370. I don't know if it's the run flat or what. The launch control was pretty fun too. Stock for stock, they are very identical in acceleration when lined up.

You can either be lucky or very unlucky with the Bmw reliability. A family member just leased a 2016 428i and within the first day, the tpms went out and they had to change out all sensors and antenna. With out warranty, that would cost around 20 Benjamin franklins. All German cars have too much unnecessary computer chips that will break sooner or later. There is a reason most people lease. I wouldn't dare touch one without certified or extended warranty.
Have you considered leasing a new model? Free maintenance too.

Although my 2011 Z is mostly reliable after 63000 miles of hard driving, it did had some issues.
-steering lock left me stranded for 3 hours until I found the wonderful info in this website
-rear axle had to be lubed or else it clicks

Good luck on the decision