The Goodwood Festival of Speed delivers a concentration of past F1 drivers and racing legends that boggles the mind. As you wander around Lord March's motoring garden party it's impossible to avoid bumping into racing heroes from all disciplines.What's rarer is to meet with a current F1 world champion who, after reaching the pinnacle of the sport, stunned the world by announcing retirement.Nico Rosberg claimed the 2016 Formula One world championship after a season-long toe-to-toe with Lewis Hamilton. Then, on 2nd December 2016, he performed the mic-drop of the decade, announcing his retirement from the sport with immediate effect.Since then his social media feed has portrayed a fascinating insight into the world of a man freed from the pressure cooker atmosphere of the F1 circus, and content in the knowledge that he's been there, done that.We caught up with Nico just before he headed off to the paddock to drive the 2014 Mercedes AMG W05 up the hill - the first time he'd been in an F1 car since last season. (You can watch his sheer disregard for lawn maintenance in the videos above...)Top Gear\: How is life after F1, and do you miss it?Nico Rosberg\: I can still get the thrill of driving a racing car. I go go-karting regularly, so that's still there. Of course, there's going to be some things that I miss, that's inevitable, isn't it? For me it's more about the excitement of looking forward now.TG\: Given how big a shock your retirement announcement was, was it something you'd thought about during the season?NR\: No, I never thought about it in the lead up, because I signed a new contract in the summer, which cost me a lot of money to do also. It just came about when the realisation was there that the championship was now in my control and my hands. 'This is real, I'm going to win this', and then I thought 'sh**, it would be perfect'.The feeling just came about in me that I've been fighting with intensity for 20 years, driving in Formula One for 11 years getting better, better, better.It just felt perfect, I love a book with a great ending. This is the perfect possible ending for my Formula One book, for my career, and just feels beautiful. That's what it's about in the end, it's a personal feeling and I'm sitting here now and it's just awesome.TG\: How do you replace the buzz of F1?NR\: Well of course, I'm still competitive and I'm still the guy who wants to win, that's always going to be there, that's not changed. But that's going to be in different directions.I'm more in the business world now. It's early days of course, but I'm already very busy. I'm not in anything where millions of people can join into my journey, and that adds an extra power really. It's an amazing experience to have so many people join in your journey, and I would like to try do something in that direction but that's going to take more time.You can't just say okay, here's the new thing I'm doing and it's going to be just as exciting for millions of people as it was for me driving my race car, you know.TG\: You're clearly still watching the races, so how are you enjoying the season from your new perspective?NR\: I'm sitting in front of the TV excited because the racing is great. It's great for the fans I think, it's awesome, and they're going in the right direction.TG\: And the recent incident in Baku - what's your take on that? Are you glad not to be involved in that side of things any more?NR\: I don't know, I'd be happy to be involved in some battles like that and competing in that sense. Have they spoken? Anyway I am the guy who knows Lewis best, I think, in the whole of the racing world, so I think I'm probably in the best position to judge it, and he didn't do it on purpose.TG\: And in terms of your relationship with Lewis, when was the last time you guys spoke?NR\: We see each from time to time.TG\: Are you still mates?NR\: Two words, best friends [smiles].TG\: Really?NR\: No.TG\: Do you miss the rivalry?NR\: It was great... Not everything about it was great, some stuff was too intense.TG\: As someone who knows him and has competed against him, where do you think he ranks in the list of all time F1 drivers?NR\: Well you just need to look at the statistics and that says it all. He's going to have the most pole positions of any driver in the history of the sport. Beating Senna and Schumacher, that's pretty impressive isn't it?TG\: A common theme on your social feed is your Mercedes-Benz 280 SL Pagoda. You're clearly enjoying it, but what else is in the collection?NR\: Yeah. I don't want to speak about the others. There's not many anyway.TG\: What's next on the list for the collection? Do you want to increase it?NR\: No, no, I just like driving them. I'm not going to increase the collection. I try and fight addictions.TG\: Do you think the classic car thing can be an addiction?NR\: Sure, I was buying every single classic car magazine that was out there in the world. That's all I did\: read what values of classic cars were and how to fix them up and everything. I was completely into that. So I'm quite an addictive person, I just go from the one thing to the next, I need to keep control of that.TG\: With your new-found freedom, what's the next addiction?NR\: It's more the investing side of things because I have been lucky enough to have a fair amount of savings now, of course, from my career. I've got to do something with it, and so I'm very into investing at the moment.[At this point the next batch of cars head down to the start line and our conversation is punctuated by the bark of myriad F1 cars, Le Mans winners, the occasional drift car and stadium truck, highlighting the variety of motorsport that makes this event so encapsulating. But does any of this interest Nico?]TG\: Having conquered F1 do any other disciplines interest you?NR\: It's difficult - there's nothing really.TG\: You wouldn't do what Fernando Alonso did and try and claim a triple crown?NR\: For me Indy is too dangerous. I mean you see Sebastien Bourdais in qualifying on his own, he went off and destroyed himself. Scott Dixon... I don't need to risk my life in that way.TG\: Do you think today's drive in the W05 might change that?NR\: No. I'll enjoy it and for me it's a closed chapter and I'm very, very happy with it. There's nothing that can make me want to go backwards like that.TG\: How big a challenge is it to drive an F1 car up here?NR\: I don't know actually. It's massively bumpy, and it's a bit of worry to go flat out. Today I think I'm going to go fast, for the first time. I think today I want to go fast. You can't see where you're going either. Maybe I can look at a bit of a YouTube video or something.[We discuss the blind entrance to Molecomb and I suggest looking at Nick Heidfeld's 41.6sec hill record assent in 1999, painfully conscious of the fact that I'm telling the current F1 world-champion how to suck eggs.]NR\: He's got the record, no?TG\: Yup, set in 1999...NR\: Okay, I'm going to break that today.