And Martin means that in every sense of the word -- fast and sleek, but also fragile and breakable.
"God has blessed that kid with a lot of tools," Martin said of the oft-injured sophomore. "I joke with him, 'You're a Ferrari.' And everything has to work right for that Ferrari to run the way you want it to run.
"When something's off, it's like everything's off."
Something has been off with Farmer for most of his time at USC. He has been bothered by hamstring pulls on-and-off since his arrival last summer, and there have been other trips to the shop, too.
But now he has been healthy the last three weeks and starting to ease into a bigger role with the Trojans -- mostly on special teams for now but also as a backup receiver and occasional running back.
"It's good that he's come back and fought through the setbacks that he's had this year," Martin said. "He's been getting more and more reps and he's looking more and more comfortable.
"As someone that had been a receiver and then a running back and now a receiver again, that's a tough transition."
Martin extended the sports-car analogy further with Farmer -- he has to be more careful when warming up than other cars, er, receivers.
"His routine, and what it's going to take for him to be ready, may be different than some other guys," Martin said. "Marqise (Lee) may be able to get out of bed, shake his legs and run a 4.4. (George) may have to stretch and do more stuff in preparation to play.
"At the end of the day, it's a bottom-line business. You gotta be ready to go when it's your time to go. I think he understands that now."
The only other Ferrari-like player Martin has played with or coached: ex-NFL receiver Donte' Stallworth. The two played together for a season at Tennessee in 1999.
"He was a physical freak like that," Martin said. "And again, Donte' had some hamstring issues.
"He was similar to him from what I remember, seeing him run, seeing him move."
Farmer moved well on the one touch he got against Colorado -- at running back. Coach Lane Kiffin threw him into the backfield for one play near the end of the game, and Farmer gained nine yards. (The play was eventually called back due to a holding penalty.)
"I think it may have been some sort of reward, to get the ball in his hands, because he had had a good game," Martin said. "Everything we asked him to do the last two weeks, he's done it."
Farmer said he's making a concerted effort to follow Kiffin's words intently.
"If he asks me to do anything, I don't have any questions about it," Farmer said. "I just do it."