The Audi A4 B8 2.0 TDI (CAGA / CGLC) is everywhere — and Stage 1 transforms it without breaking anything.
Stage 1
Stock 170bhp → 210bhp / 440Nm. No hardware needed, runs on the standard DPF, turbo and clutch (manual) or multitronic.
Stage 2
Needs a 3" downpipe + decat or sports cat, and ideally a high-flow intake. Power climbs to ~230bhp with much better top-end response.
Which to pick
If your A4 is a daily and you want a reliable bump, Stage 1 is the right answer. Stage 2 is for people happy to spend on supporting mods and lose a bit of MOT margin.
DPF on a tuned B8
Stage 1 maps don't increase soot loading meaningfully. Regular motorway use keeps the DPF healthy regardless of tune.
Related services on StageMyCar: Stage 1 remap and Audi remapping in Uxbridge.