If I were you get a NEW rx7 shell with 5spd and swap it with a S5 13BT. Or swap your NA with a S5 13BT and convert your car to 5spd. No point in getting a 20B unless you got the dough. 13BT should satisfy your needs and no doubt if you currently have a NA Auto.

 

No, a 20B has one whole extra rotor...

That explains the poor mileage.

Kinda like if you had a 8 cyl engine and made it into a 12 cyl...

would you expect to even get into the same ball park as far as mileage??

 

I wonder, what was the stated MPG or 'KMPG' for a new, stock 20B Cosmo...?

 

The cheapest way to get a nice FC without breaking the bank is to buy somebody else's project. That's what I've noticed around here. There was a guy selling an FB with probably $10k in mods for $3,400 just a month ago. Look around, keep your eyes open... be patient. Buy from a reliable seller and you'll get a nice ride. Unless you're a gearhead or born with a wrench in your hand, a lot of this swap stuff that you're talking about is a) quite expensive b) over your head (mine too).

Good luck with your project.

Josh

 

its true, i bought my car with ~10k in mods for 4k