[Misiek]

SQLite itself isn't that slow. Maybe it's something with the SA-MP's implementation.

Code:

1000 unique queries: SELECT * FROM table WHERE field LIKE ‘unique_value%’ :
- SQLite - 0.6806 sec.
- SQLite (Memory) - 0.71688 sec.
- MySQL (MyISAM) - 0.16667 sec.
- MySQL (InnoDB) - 0.13743 sec.
- MySQL (Memory) - 0.33858 sec.

Code:

1000 identical queries SELECT * FROM table:
- SQLite - 0.77956 sec.
- SQLite (Memory) - 0.76029 sec.
- MySQL (MyISAM) - 0.86335 sec.
- MySQL (InnoDB) - 1.31506 sec.
- MySQL (Memory) - 0.77291 sec.

Code:

1000 INSERTS:
- SQLite - 74.157 sec.
- SQLite (BEGIN-COMMIT) - 0.16181 sec.
- SQLite (Memory, BEGIN-COMMIT) - 0.13252 sec.
- MySQL (MyISAM) - 0.11942 sec.
- MySQL (InnoDB) - 25.019 sec.
- MySQL (InnoDB, BEGIN-COMMIT) - 0.16452 sec.
- MySQL (Memory) - 0.08914 sec.

(from http://bukox.pl/php/sqlite-alternatywa-dla-mysql/)

And when it comes to inserting/updating/deleting a lot of data, use transactions, which are present in SQLite (unlike MySQL's MyISAM for example).
You've got to remember, that G-Stylezz's MySQL plugin features threading, so queries won't freeze your server until they are done.