Westley swooped to sign the dynamic midfield man on Monday night after he has enjoyed another fantastic season for the Reds in the Doc Martens premier division.
But despite the arrival of another free-scoring midfielder, Westley insists Carroll, 26, is NOT a replacement for fans' favourite Lenny Piper, whose future at Farnborough remains uncertain.
Since signing from Dulwich Hamlet two seasons ago, Carroll has scored an impressive 33 goals for Crawley in just 102 games — showing the kind of form which won him selection for the FA Representative side last season, playing alongside new Boro team-mate Gary Holloway.
Indeed, this season, he netted 16 times on his way to the Supporters Club and Player's Player of the Year awards. Carroll will certainly be missed at Broadfield Stadium.
Reds fans are slightly concerned at present with a sudden exodus of players leaving Crawley this summer.
Key man Carroll has been followed out by top scorer Rob Collins and ex-Boro stars Dave Harlow and Jimmy Dack.
Dack has been an integral part of the deal to lure Carroll to Boro, according to boss Westley.
Sporting a broken collar bone, courtesy of frolics with Boro striker Miguel de Souza, the popular midfield man has been returning to the AIMITA Stadium to sit his UEFA B Coaching badge along with current Boro star Micky Warner, and it's Dack's recommendation which prompted Westley into action.
Speaking on the Crawley website, Carroll said: "The last few days have been really tough. I've enjoyed every minute of my two seasons at Crawley and having to make the decision to leave was one of the hardest of my life.
"I've always dreamed of playing Conference football and Farnborough gave me the opportunity to do so sooner than I expected, so in the end it was a chance I couldn't turn down."
Ironically, Carroll will be back at Broadfield Stadium sooner than he imagined as the two clubs have arranged a pre-season friendly for July 27.
Carroll's arrival at the AIMITA Stadium, Westley's first of the summer, has promptly started a wave of transfer activity which is expected to roll onto into the next few weeks.
Justin Gregory gave Boro fans to best piece of good news last week when agreeing to a new long-term contract, and he was soon followed by key striker Christian Lee, who agreed to similar terms with Westley earlier this week.
All out-of-contract players have now been spoken to and news of the retained list, and indeed Westley's three other transfer targets, will follow soon.
The first casualty of the revolution, however, is young striker Lee Riddell, who has been released on a free transfer.
Riddell came within a whisker of breaking into the first team reckoning after a storming pre-season in 2000/01, where he finished top scorer despite the attentions of several of his higher-profile team-mates.
But Riddell tragically suffered a broken leg soon after and never really got the opportunity to prove his worth, despite making a few reserve team appearances.
Westley said: "Lee Riddell is a victim of me wanting to slim down the size of the squad. I need to have every player on board capable of playing in the first team and capable of winning the championship. I think that's come a little bit early for him.
"Having a squad of 25-plus players makes it very difficult to develop your players on a one-to-one basis, we have to cut the squad and Lee has become a victim of these plans.
"I am sure, however, that wherever Lee goes, he will prove to be a good signing for someone, possibly in the Ryman League.
"As for Danny Carroll, we've got a good player here. He scores goals from midfield, is a good athlete and is workmanlike, arriving in both penalty areas.
"The best thing about Danny Carroll was that he agreed to sign for this club before the subject of money was even mentioned. That is a rarity these days.
"He had hunger in his eyes, wants success and chose Farnborough straight away. That's the type of player who appeals to me.
"Carroll is a very different player to Lenny [Piper]. With Lenny, you need to get him on the ball, Danny is good in the air and is a good athlete covering box to box.
"As for the other changes, I'm in no particular rush. We have finished the season with a good side, one which I feel, with three more new additions, can make a challenge next season.
"There are areas in the team I want to improve and I have those players in mind in order to improve them.
"Justin Gregory signing on is a big boost. Justin has worked very hard since breaking his ankle, I know how hard it is because it was exactly the same that happened to me.
"I understand he's been a bit harsh on himself, I thought his form was OK when he came back. But Justin is a player who could play at a much higher level and he naturally sets himself very high standards.
"I'm also delighted to have Christian on board because he is a class act. He is also one of those lucky players who seems to play in winning teams, like Nathan Bunce.
"Those players are very handy to have around.
"Not only that though, Chris has performed extremely well, holding the ball up, hitting the channels well, creating goals and scoring as well."
With Westley aiming to trim down his squad this summer, and with three new additions likely to join the ranks, a number of players are fearing their Farnborough Town futures.
Westley could release as many as six or seven squad members with the likes of Keith Dublin, Gary Crawshaw and De Souza all seeking contract extensions.
Boro skipper Steve Watson was part of the England non-league squad that drew 1-1 with Wales at
Boston on Tuesday (May 14) night.