i tried taking the XFG and XFR and get close to a 2001 jetta 1.8t but it wasn't easy. LFS does not allow factory spring rates with ride height very easily. you have to jack the ride up all the way, but live camber seems to hold with the McPherson strut the game uses). a majority of the mkIV A4 chassis golf/jetta/NB (1999-05) came with springs between 130 lbs/in and 170 lbs/in.
Shock rates were more of a guess based on steering response in the XFR. I have Bilstein HD's which are a lot stiffer than even the factory "sport" shocks. The difference was night and day and the initial turn in was like night and day over factory. Weight of the mkIV Jetta/Golf could not be obtained so I went for a close power/weight ratio. Springs would have to be softer to accommodate less sprung weight.
This is what I came up with for a 2001 Jetta 1.8t:
Height: 110/100 m (REAR/front)
Springs f/r: 160/140 lbs/in (160lbs/in = 28 N/mm)
Damp: 6 Ns/mm
Rebound: 6 Ns/mm
Sway f/r: 20/30 N/mm
(above is XFR, to get the proper power/weight ratio)
Revised:
XFG to get proper suspension/tire combo
Ride height: .170/.180 (rear/front)
Spring: 20/29
Damping: 3.3/5
Sway: 37/48.5
Ballast: 190kg @ 100% front. gives 63.3/36.7 (could be less, 55/45-60/40 feels good also)
Camber: 1* front, 3* rear
My "spirited" and track setup use 38-42 PSI. 35-38 PSI gets fairly even tire wear with mostly spirited street driving, outsides of the front are generally warmer up front, and the insides on the rear tires.
With Bilstein aftermarket shocks:
Damping: 6/9 (rear/front)
With RSB:
Sways: 100/48.5 (rear/front)
i had some trouble with the brakes because the MKIV A4 chassis is designed so the rear locks up first with no rear passengers/cargo, kicking in ABS, and keeping the car straight for the most part, in the game the rear slides out under hard braking in corners because the suspension is so soft.
edit: factory toe/camber: front .6-.9*. rear looks around 3*. 1/8" toe in(.348 degrees, .174 per side). when the rear tires are at 35/lbs the outside edge of the tire does not contact the ground.
I have a Bildon Motorsports (VW Motorsports) Rear sway bar . This is an internal RSB. Internal being it sits in the rear axle beam and not outside. It adds about 20 lbs to unsprung weight. External adds to sprung weight. Usually 8-15 lbs. I could not obtain the exact torque rate this rear sway provides, but a similar design states 363 lbs/in of roll resistance, which is around 64 N/mm. When I try to jack up the rear left tire, the front left comes off the ground at the same time as the rear tire. Same thing when I try to jack up the front, the rear comes off at the same time the front does. When I up the rear sway on the XFR to around 80-110 it seems to handle like my car does with the additional rear sway. I say additional because every rear sway design i've seen for the MKIV A4 chassis compliments the factory sway. Front sway bars are replacements.
Factory rear sway bars:
Golf: 21mm/18mm (front/rear)
Jetta: 23mm/18mm
GTI and most factory sport suspensions: 23mm/21mm
R32/TT/4-motion: 20mm/18mm
Other rear sway specs:
Neuspeed 28mm solid bar external RSB: 428-560 in-lbs/degree or 260 lbs/ft (45.5 N/mm)
H-Sport 30mm external: 284 lbs/in (50 N/mm)
If spring rate is linear with solid bar diameter you could figure it out the factory rates using the 28mm @ 45.5 N/mm and 30mm @ 50 N/mm. If I get a chance I'll mess around with this in single player later
(EDIT: i did this and in LFS it appears to be mostly correct, the car ends up with a bit over steer compared to what i remember of the factory handling, and has too much over steer with the rear sway values)
Taking in as much ballast as possible only brings the weight up to around 2200lbs on the XFR. My 2001 Jetta is 3180 lbs. Thats with over a 1/2 tank of gas, myself, my rear seats, spare tire and and some junk. IIRC it was 2900 with 1/2 tank without me and no spare, and around 2750 when I tracked the car with no rear seats, no spare, no passenger seat, no subwoofer. Weight should be round distributed around 60/30 to 70/30. At my curb weight of 3180 and 245bhp it puts my car around 155 bhp/ton. (210 hp at the wheels) The 2.0 should be around 85 bhp/ton with around 100 bhp (115 or so at the wheels).
1 N/mm = 5.710146 lbs/in (i googled "N/mm to lbs/in", there were multiple sources so i didn't have to do the conversion myself)