Hey Jon,
The Bilstein B4s will ride similar to standard sport shocks and they're inexpensive as you noted. The Eibach Pro-Kit seems to go well with them. I run Eibach springs in my car (well, AC Schnitzer but they are made by Eibach) and have had no issues. Eibach makes a high quality product.
For bumpstops, check out this thread:
http://www.e90post.com/forums//showthread.php?t=699650
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2024 BMW M3 Sedan Frozen Pure Grey II/Fjord Blue, 6MT
Past: 2021 Z4 M40i Frozen Grey II/Black Alcantara | 2017 F30 340i Mineral Gray/Coral Red, 6MT | 2011 E92 335i Le Mans Blue/Black, 6MT