1) Is the beginning of the game as tedious as in Gran Turismo 3? With having to repeat the same beginning races over and over and over again in order to get enough cash to really get started?

2) How much better are the graphics over GT3?

haven't played it but...
1) most likely
2) noticably better

Personally, I thought the game looked pretty much the same except for the cars. They seem marginally better.

But yeah, the beginning is pretty much the same. But...more so. You're pretty limited as to what races you can start with. My advice is to get a decent, quick car and do the special events races. Quite easy and you get PAID (mostly with bonus cars that you can win again and again).

You can import up to 100,000 from your gt3 memory save I believe, allowing you to bypass the initial tedium

Much less tedious at the start. Although I enjoyed struggling through the first few competitions with a car that did not deserve to win in GT3.

You still have to do all the licence tests to access the later races, that can be a little tedious. But at least you get a car as a reward for getting a licence.

The graphics are HEAPS better. They're amazing. Some of the new courses especially like El Capitain and Costa Di Amalfi have great scenery.