Quad-Exit Exhaust and TOM'S Diffuser on a Corolla Hatchback

By REMARK Exhaust | Published: 2026-11-02

Category: How-to Guides

Fit a quad-exit Sports Touring exhaust and TOM'S diffuser on a 2019–2022 Corolla Hatchback with a step-by-step process that avoids common alignment and clearance mistakes.

Quick answer

Install the TOM'S Racing rear diffuser first, then hang the quad-exit Sports Touring exhaust and adjust tip height and side-to-side spacing last. Doing the diffuser first gives you the final cutout and mounting points, so you can align all four tips to the diffuser openings rather than chasing gaps after everything is tight.

Why the diffuser goes on before the exhaust

The quad-exit bundle pairs a catback system with a TOM'S Racing rear diffuser kit, and the diffuser defines the openings your tips must sit inside. If you hang the exhaust first, you risk tightening clamps around a tip position that no longer works once the diffuser is fitted. Mounting the diffuser first turns the exhaust into a final alignment job instead of a compromise.

This order also matters on 2019–2022 cars because the factory rear bumper cover and diffuser are removed or modified to clear the quad tips. Once that trim work is done, you can see the true clearance around each tip before the exhaust is fully tightened.

What to check before you start

Confirm you have the factory donut gasket and spring bolts that the system reuses at the OEM pipe connection; the catalog notes these are the connection hardware, so don't discard them during removal. Also check that your tip option matches the look you want before installation, because changing tips later means loosening the rear section again.

The product listing does not publish pipe diameter, tip size, or weight, so measure your own bumper clearance and decide on tip spacing from the actual diffuser openings rather than from assumed dimensions.

Where alignment usually goes wrong

Most quad-tip complaints come from tightening every clamp before the system is centered. The rear section can shift several millimeters at each joint, and that movement is enough to make one tip sit lower or closer to the diffuser edge. Leave the rear clamps snug but movable until all four tips are visually even.

A second common issue is mixing up the diffuser's mounting points with the bumper cover's original holes. Test-fit the TOM'S diffuser with the hardware loose, confirm the cutout edges are symmetric, then tighten.

Step-by-step: quad-exit exhaust and TOM'S diffuser install

Remove the factory rear diffuser: Unbolt and release the OEM diffuser from the rear bumper cover, keeping the fasteners organized. Common mistake: forcing the clips and cracking the bumper cover tabs. Check the bumper cover for cracks before fitting the new diffuser.
Test-fit the TOM'S Racing diffuser: Hold the diffuser in place with hardware loose and check that the cutout edges sit evenly on both sides. Common mistake: tightening one side fully before confirming the opposite side lines up. Mark any trim line before cutting or drilling.
Trim or modify the OEM diffuser area if needed: Follow the diffuser's cutout shape and remove only what is needed for clearance. Common mistake: cutting too much at once instead of sneaking up on the line. Re-test-fit the diffuser after every trim pass.
Mount the TOM'S diffuser: Tighten the diffuser hardware evenly, working side to side so the gap to the bumper cover stays consistent. Common mistake: over-tightening one fastener and pulling the diffuser out of shape. Confirm all four tip openings are clear before moving to the exhaust.
Remove the factory exhaust: Support the OEM system, unbolt the rear section, and keep the factory donut gasket and spring bolts for reuse. Common mistake: dropping the pipe and damaging the OEM gasket surface. Inspect the donut gasket and replace it if it is cracked or flattened.
Hang the quad-exit Sports Touring exhaust: Lift the catback into place, connect to the factory piping using the donut gasket and spring bolts, and leave the rear clamps snug but movable. Common mistake: fully tightening the rear section before the tips are centered. Keep the rear joints loose until all four tips are positioned.
Align all four tips to the diffuser: Adjust tip height and side-to-side spacing so each tip sits evenly inside its diffuser opening, then tighten the rear clamps. Common mistake: aligning only the outer tips and ignoring the inner pair. Check tip spacing from behind the car at eye level, not from above.

Product facts

Sports Touring Exhaust [Quad-Exit] + TOM'S Racing Rear Diffuser Kit - Toyota Corolla Hatchback (2019~2022): Bundle includes the quad-exit catback and TOM'S Racing rear diffuser kit, and the listing notes the OEM diffuser must be removed or modified. Plan for trimming or replacing the factory diffuser before the exhaust goes on, so the tips have a defined opening to align to.
Sports Touring Exhaust [Quad-Exit] + TOM'S Racing Rear Diffuser Kit - Toyota Corolla Hatchback (2019~2022)