Hi. Lots of threads on exhausts. I went for the Eisenmann Race after a fair bit of research. It's hard to make a decision based on YouTube vids but maybe you can get to hear some in person. I live in Northants. You can listen to mine. It looks good too (unlike the BMW one).
I have added spacers to make it look a bit meaner. 18mm front and 15 rear. Very happy with them.
Most essential is a black grill.
The angel eyes are a popular upgrade. I went with the cheap option - GP Thunders. Not all that bright but a much nicer colour than stock. Lux is the choice if you want to spend more.
That's my 2 cents worth