I haven't heard bad things about Dan (Premier Z), although he does seem to be a bit on the expensive side. Goku could be right, I just havent heard those same things. Z-Fever (aka Fever Racing) does have a bad reputation and I would use caution in dealing with them.
If you need something done in the Tampa area, I would suggest you speak with Harry at Z-Tuner (ztuner.com), who has a great reputation and he would be my go-to guy. If he can't do it, he can probably give you the low-down on others in the area.