Wheel size
 

I recently purchased a Mazda Speed 2004, 27,000 miles. I drive the car in a spirited fashion and avoid wet roads when I can.
Should I keep the stock 17” and choose a good all weather R rubber tire or should I change to 15” wheel with a great all weather R tire
with a small diameter wheel should I lower the car?
I’m looking for great handling
Is the small Enchilada a good unit?
what adjustable coil overs should I buy?
Is there a reliable ECU chip available?