You might find the B12 Sportline (red springs) a tad stiff for daily use if you want refinement, not that the standard ride quality is especially plush to begin with!
B12 Pro (black springs) is what you need for a more compliant ride, but Bilstein's catalogue doesn't list such an option for the GTI. Only the lesser models. If you see any online places listing a Pro kit for GTI/ED30, be vigilant. It doesn't officially exist.
Anyway, if the Sportline is of interest...
B12 Sportline for 55mm strut - https://www.bilstein-shocks.co.uk/products/46-194916
B12 Sportline for 50mm strut - https://www.bilstein-shocks.co.uk/products/46-183774
Yours should be a 55mm strut on a 2006. The dealers are apparently unable to tell you which size is fitted from your VIN, but it's largely accepted that only very early GTIs came with a 50mm strut, i.e. 2004-2005. 50 and 55mm being the outside diameter of the (front) shock absorber.
I would go with Shoduchi's recommendation of B8 and HR springs. B6 - B12 is the same damper. The only difference is the droop length.
Cheap coilovers have a bad reputation, but the good ones are more flexible than fixed struts as you can fit spring rates & lengths of your choosing.
Thank you your informed reply, my car is actually on a ‘58 plate so towards the end of the Mk5’s so from what you’re saying most likely 55mm.
I used the car on Saturday and the ride is too firm on the road for my taste although it seemed noticeably better at higher speeds. I will only use the car a few times this year on track so I’m beginning to lean towards the Racing Line set up that majors towards a decent ride from what I’ve seen posted on here. My hestitation is the idea it falls apart when pushed... Sometimes I like to press on and I’d hate to find I’ve ruined my cars ultimate handling capability!
That was exactly my objective as well. Decent ride quality when plodding along but still feeling keyed into the tarmac at all times, and when the mood arises, it's a go kart in the corners.....but without throwing you out of your seat over mid corner dips/bumps in the process. It's a difficult pile of boxes to tick with one setup.
The Racingline setup is a definitely an improvement over oem in most areas. It rides better on typical minor and A roads whilst also shifting the base car's wallowing at speed, so 2 boxes ticked there. The only box it doesn't tick is the 7/10ths and harder cornering. I experienced front arch fouling fairly easily. Some of that is down to ride height, and some of it down to spring rate. I also experienced some unexpected and severe understeer on a particular corner the stock suspension and my subsequent upgrade to coilovers don't even notice. I put that down to the unpredictable nature of progressive springs.
As above, thicker ARBs will help reduce some of that lean into corners, so should solve the arch fouling. It's a great kit for the money. Other than that, my only other recommendation costs 4x as much. I think the Bilstein kits will be too harsh for you.
You could try Racingline dampers with the standard springs. The oem setup is very much geared towards urban responsiveness, but get it on a bumpy, winding B road, it falls apart. The RL dampers ought to iron that out.
