In answer to your question I would never recommend you go back to Sportline suspension. The Eibach sportline springs are quite possibly the worst on the market, very unforgiving and firm. Although it doesn’t sound like you have the most forgiving setup now.
Lots of decent coilovers available for you, fitting and aligned correctly you can have both low and comfortable whilst retaining the sporty handling when needed. This will also give you the option the set the height you want and not the height pre-set by the springs.
Im not sure where you are in the country but if local to us, please pop in and we can look at your existing setup if and give advise as to where you should spend your money for the best results.
Despite the comment above the Bilstein B14 Komforts are excellent, with great drops and comfort. Speak to us about a deal on these - we offer a deal for forum users. We have fitted many sets already since their launch.
We also offer coilovers from ST, KW and Eibach so plenty of selection from the very best manufacturers out there.
Get yourself out in a vehicle running the suspension you are after to make sure its right for you, too many people are making their decision without trying for themselves and regretting it after.
HTH