Hei Tor,
again you dont need it, there would be a ton of pro mechanics that dont use any branded special tools, but im not a pro. I have/had a few 266's a few 272's and a few 288's so it made sense for me to get them. They do work very well. The only one ive had a prblem with was the flywheel removal tool Part. No. 502 51 49-02, the ring that bolts to the flywheel is too thin and prone to bending when trying to remove old stuck on flywheels......
alternatively you can use the closest size socket as a drift for your seals, just make sure they go in square and seat to the correct depth. On that note the special tool Part. No. 502 50 53-01 is great for installing the seal over the crankshaft lip.