Here is a summary of what I know through owning, modding and researching 2ZZs for over 2 years:
- Celica GTS is 130 lbs lighter than the XRS (2520 lbs vs 2650 lbs).
- Need two door coupe or 4 door sedan?
- Celica GTS handles better than the XRS (0.85g vs 0.89g). Celica GTS was actually the best handling Celica ever. Celica GTS in a direct comparison test with DC2 Integra Type R almost tied the Integra Type R in slalom and track lap times.
- By looking at airboxes, Celica GTS intake was better optimized for high rpm breathing than the more conservative XRS intake that was meant for better fuel economy and sound muffling.
- 2003 + Celica GTS have drive by wire as opposed to XRS that has mechanical cable throttle.
- 2002 and 2005 Celica GTS had rev limiter set at 7800 rpm (making them the slower Celica GTS models). All other years, had the same rev limiter as XRS at 8400 rpm.
- XRS was rated at 10 HP less than the Celica GTS(170 HP vs 180 HP), but my extensive look at Corolla XRS and Celica GTS dyno database at newcelica.org tells that with intake/exhaust, they both put out close to 168 - 172 whp@7800 rpm (190+ HP at the crank).
- 2000 - 2001 Celica GTS dynoéd the highest especially compared to the 2003+ Celica GTS mainly because of higher powertrain loss due to drive by wire throttle system.
- Only problems existed in the earlier Celica GTS models where lift bolts were breaking. It was later on fixed through fitting second generation lift bolts that were stronger. XRS has the second generation lift bolts so no worries there.
- Stock Celica GTS lift kicks in a bit earlier than the stock XRS (6200 rpm as opposed to 6600 rpm in XRS).
- XRS had the re-tuned ECU that was tuned for a flatter torque delivery especially at low rpms at the low engine speed cam.
However, tons of dynos have proven that Toyota distorted facts by saying XRS peak torque is at 127@4400 rpm when it is still 133 ft lbs@ 6800 rpm. It was a marketing strategy to make the car sound more easier to drive in city traffic through declaring peak torque at 4400 rpm.
- Best tested stock quartermile for XRS is 15.3@92 mph and 15.2@93 mph for Celica GTS (both by Motor Trend).
Cheers.