Hey Javi - just for you I ran out to the garage and grabbed both from the parts shelf. Here's a side by side with a standard 3-spoke and a Tequipment 3-spoke (you know I'd have one
).
Without digging around for a micrometer to measure, they both feel the same in my hand. The two thickened leather grips at 10 and 2 on both wheels fit exactly the same way in my hand, as do the carbon fiber grip vs the leather grip. Eyeballing both, I can't see any apparent difference in diameter on either wheel. I think you'd be correct in having them keep the grip the same diameter as your stock 3-spoke.
Who are you having do the work for you?
BTW - I didn't know you had Sport Seats - cool!
2002 Porsche Boxter S
2001 Porsche Boxster S
1999 Porsche Boxster
1999 Porsche Boxster
1999 Porsche Boxster
1999 Porsche Boxster
2000 Porsche Boxster
1999 Porsche 996 C4
1972 Porsche 914
1984 Porsche 928S
1984 Porsche 928S
1985 BMW 635 Csi
Hybrid Mode
