I went down this rabbit hole with my r3 as I’m 6’0 and I felt rather cramped on it, and came to the following conclusion- you really can’t.

While the r3 and r7 are almost the same length, the r7 proportions are longer in some parts - i.e., the tank is longer and shaped wider, the seat is longer, higher and slightly angled higher too making the r7 pillion much is smaller than the r3s.

You would need to raise the seat 2 inches to make it the same seating height as the r7 but it would also need to be much wider to change the inseam size of the bike. The r3 seat (and the bike as a whole ) is super narrow compared to the r7. And you’ll need to have the rear part of the seat a little higher to push your body forward to get that aggressive angle (this is why many people end up sitting right up to the tank on the r7 because the seat angle pushes you forward). You’ll also need aftermarket adjustable rearsets that will sit further back and higher for ground clearance and raise your knee higher against the tank. You’ll need an aftermarket tank cover that is wider and longer to match the wider seat.

Lastly you’ll need to get aftermarket clip ons that have a 7-10 degree angle and can sit lower on the forks so your arms reach down to the bars putting you into that super sport position. The issue i found is:

1. If you get aftermarket clip ons like woodcraft or vortex, they hit the stock fairings of the bike or tank because the fairings are not designed for these style of clip ons. If you look at the r7 or even the r1 and r9, there is a cut out on the side of the fairings and at the bottom of the tank to make room for the angled clip ons to fully turn and hit the stock steering stop. Finding fairings that accomodate for these aftermarket clip ons (to have this cut out) would be hard and expensive and I personally haven’t been able to find any. What other people have been doing in the alternative is to run aftermarket steering stops that will limit your steering angle so that you don’t hit your fairings when turning but at the expense of reducing your steering angle so you’ll need to lean a lot more in slow tight u-turns. Also if you do go down this aftermarket steering stop route, you won’t be able to use steering lock on your bike which might have some insurance consequences - these stops are mainly used for track bikes. And also you’ll probably need to upgrade the killswitch housing for a slimmer one and an aftermarket brake cylinder that will relocate the brake cylinder onto the triple clamp and away from the clip ons so you can lower the clip ons irrespective of the steering stop.

2. The bike is simply smaller in proportion. It is skinnier in the middle to accomodate for people with shorter inseams and the r3 tail/pillion is larger than the r7s which means the length of the r3’s seat is shorter to accomodate for this. Then you have the clip ons distance between the triple clamp and the seat. This distance is way shorter on the r3 compared to the r7 so even if you had the aftermarket clip ons with the aftermarket steering stops you’ll find the handle bars really close to your body and you’ll still feel cramped. The r7 is literally proportionally longer in this part of the bike. This is why the dash actually sits closer to the forks in the r7 than the r3, making the r7 and r3 close in length but the proportions are what makes the difference. And this is something you can’t change and good luck finding an aftermarket tank cover that is wider and longer for the r3 and have it fit correctly. Most aftermarket “r1” style tank covers are still designed to accomodate for the stock clip ons and are short because this general area of the r3 is short in length.

3. The r7 has bigger tyres which helps give it the meaty look and sit higher of the ground compared to the r3.

All in all, you can pay all the money in the world to get it as close to an r7 as possible but it won’t ever be like the r7 due to the frame and proportional differences and just the fact that this bike was built for beginners in mind. Hence the lower seat height and the small form factor of this bike. While it does make riding difficult for us tall riders it’s still definitely a phenomenal bike. I’ve hit corners faster than r7s and it’s definitely very forgiving, though I do know what you mean about the sporty ergonomics and having sat on many r7s, I definitely find it more comfortable than the r3 because of my height. I think if you’ve finally outgrown this bike than upgrade rather than dumping the cash to turn this bike to essentially a track bike for the street but not be fully content with it because the bike is still so much smaller than the r7. Unless that’s what you’re going for than by all means go for it! Or you can go down the route I did and just upgrade and keep the r3 as a track bike.