Tunes: JB4, Procede v5, Cobb AP, Active Autowerke, ect, ect.
Downpipes : AR Design 3'' N54 Downpipes (Catless), Active Autowerke N54 3'' Catless Downpipes, CP-E downpipes, ect
Front Mount Intercoolers: Helix Stepped FMIC, HPF FMIC, Big Tom FMIC, AMS FMIC, Spearco FMIC, CPE FMIC with built in oil cooler, and many others.
Intakes: aFE Dual Cone Cold Air Intake, BMS DCI, Many other DCI's...just google 335i DCI, Dinan, Injen, ect.
Exhaust: HPF, Borla, Supersprint, AMS, Racing Dynamics, (just search!
If you worried about longevity I would just get basic mods done like Intake, Exhaust, and running a mild tune that only increases boost by a few PSI like JB+.