If you're looking for the most comfortable ride I would not recommend Tein or BC. They are good
budget coilovers that will lower your car and not break your back but I would not call them comfortable by any means. If you are looking for the most comfort I have 3 recommendations.
1. RS*R Sports-i Coilovers. Most comfortable coilovers you'll probably ever experience. Hand made in Japan and every little detail is geared towards a comfortable and civil experience from the Bushing Style Mounts and Roller Bearings to the Rubber Spring Seats. They are still very sporty but I have experienced better than stock ride quality from every car I have driven in with them installed.
2. KW Coilovers (V1 or V3). Because they use the stock Strut/Shock mounts they retain a little more vibration isolation and the german construction on them is very solid. Well valved they are going to be much more comfortable than your previous two options and perform better.
3. Get a good spring and shock combo and replace your strut/shock mounts if worn out. This will provide you with a pretty comfortable ride and perform well. Not much different than the Tein Street Basis kits.
Here is a link to a forum member's review of the RS*R Sports-i Coilovers
RS-R Sports-i Coilovers Review
If these options are out of your budget I highly recommend waiting and investing in a good high quality suspension.