Another big-guy in a Miata thread...
 

I'm looking into buying an NB2 Miata with leather interior, and I'll be driving this car for about 6 hours back home IF I purchase it. The ONLY Miata I have driven was an NC Club and I did fit quite snug but still comfortable. Headroom was to the absolute limit when I didn't have the top down. I've read quite a few forums about fitment, big-guy mods, etc, and I can't seem to find a straight answer. I'm 6'4 with a 32 inseam. I also read that the NC was less roomy. Here's a picture of me in the NC https://i.imgur.com/67iZmIT.jpg

Only thing you can do is try one on. It is going to depend a lot on how you are proportioned and if you can find a comfortable seating position. You will be able to fit, just what mods you have to do will depend on personal preference.

I have a 2001 with the leather seats. Seat shoved all the way back, with the most decline possible.

I'm only 6', and I have a proportionately short torso, and my hair grazes the soft top if I sit up straight. I don't touch the hard top.

I can only guess your torso is 2-6 inches taller than mine, you will not fit under the soft top or hard top.

The seats are quite comfortable, just drive with the top down. You will definitely need a foamectomy at the minimum, probably different seats, floor modifications, rails....

Have fun!

My NAs with the top up was slightly less comfortable than my NC with the top up. 6'5" if that helps. In the normal NA I regularly hit the roof supports.

Lots of problems getting my knees under the steering wheel on either, and the seat has to be in just the right spot or I get ongoing knee pain. Puma's help a ton. The track car has a Kirkey bolted to the floor, otherwise I wouldn't pass broomstick. YMMV.

My 6' 8" friend fits in my NC just fine. He is substantially more cramped in my NB. He is evenly distributed between legs and torso length.