The best VR4's ran high 13's. Turbo Buicks (86-87) run VERY high 13's to 14.3's or so. BUT, VR4's are VERY expensive to mod. Put $500.00 in parts on the Buick and it will run a high 12. Sooo.....the choice is easy, Buick would win with-out breaking a sweat!!
Ken B.