The downpipe is available from Voldat , Mark Richardson has had them built or the ones from O/S but the ipd one is smaller diameter, beware.
Rear Sway Bar upgrade is essential as the heavy front pushed at the slightest provocation and HARDRACE/WHITELINE/KC_? parts for strut brace, control arelms and linkages , Powerflex bushes are upgrades I have sitting ready to install to help the front end and also my tired suspension.
I imagine the B8s will be harsh but you come from Lotus!
I put R-Design low mileage springs and shocks to good effect but better on front will also help the understeer.
Driving a V60 Polestar I found it better but still needs understeer help.
Elevate intakes are junk, just put a panel filter in , Volvo do great airboxes.
Elevate intake mani seems to be a slight increase but intercooler and DP biggest gain, TDI TUNING box is a BIG power gain but not a comprehensive one like Hilton.
Jaguar wheels are available cheaply , considering the cost of refurbished job ...and better fit offset wise , centre cap decals from Dave Barton unless you like a kitty on the Jag ones.