15x8 with no regrets.
I have a set of the 15x9's with 225/45/15 rs3. On my 01 NB with Tein flex's they looked and fit fine without any modifications to the car. However... you must purchase a set of 3mm spacers for the front or the inside wheels will rub and scrape against the control arms at max turn in. Concentric 3mm spacers will cost you an extra $180 (www.motorsport-tech.com) . The 225/45/15 is a nice tire but does get a little sidewall stretch on the 15x9 so it is the narrowest you can gowithout going taller than stock 22.8 inch. The low cost rs2 and rs3 are quite often on backorder. You will not be able to go down to a 195, 205 or even a 215 for less expensive daily use. Some have said to me the 225 with 9's combo is a little harsh but I did not find it to be. Also to consider is the 1/2 pound extra weight at each corner just for the wheel. The 225 tire itself is IIRC about 3-4 pounds heavier for each corner. Depending on you tire choice with the 9's you will be adding almost 5 pounds of unsprung weight to each corner. I did not think the car felt as light and tossable as it was with the factory Enkies and 205's but it did really stick and took some effort to get a drift.
For daily driving, fun runs and cost of living expense I would rather have the 15x8 with 205's.