I raced a 00 GT convertable last summer with my bone stock 86 mustang Gt. The chick was all brag about how fast she was she had a K&N filter and some 4.10 gears, with an auto. My poor old 86 has 155k miles on it, never been rebuilt, is a 5-speed with 2.73 gears, not to mention I hadn't changed the air filter in mine in like 2 years...lol.
We were dead even. At about 90 I started to pull away. You should smoke the 99 if he is stock geared. I had a friend with a bone stock 90 5.0 convertable and his would pull mine. You should seriously have no problem, I wouldn't hesitate to race him...or anyone else for that matter...but that's me
I'd say make it a race for pinks! (j/k)