The TOG'* are a QUALITY header and you can't beat the warranty. When my dad got his TOG'* he didn't look at them too closely, once they were on the car he noticed that one of the welds was bad and there was a hole about 1/8" in diameter in one of the welds. He contacted TOG and they sent him a new one no questions asked without even seeing the bad header. Haven't really looked too closely at any SLP'*, I've seen them on cars before, and they look good, but I haven't looked really close at them. The TOG'* seem to be better flowing based from what I've seen on ClubGP, and based on logic by looking at the two headers and comparing the flow through them, but I could be wrong. Personally, I am somewhat biased and prefer the TOG'*, but I honestly think they are a better header. If I had to choose between one of them, I would drop the extra cash and spring for the TOG'*.
1990 Maroon Grand Prix STE McLaren 3.1 Intercooled Turbo, 14.695 @ 94.49 on 12psi before cam/heads/etc.
1990 Bright Red Grand Prix McLaren 3.1 Intercooled Turbo, 14.819 @ 92.72, 189whp
1999 Grand Prix GT 9.75:1|K&N|160 tstat|No Ubend/Cat/Res|UD Pulleys|Ported M90/TB/Heads|XPZ|2.55"|Pacesetters|Stage 2 I/C. 12.442 @ 112.78
2000 Blue Bonneville SSEi Supercharged Gutted Airbox|K&N|3.4"|1.9'*|WP Pulley|Custom DHP|180*stat|41932'*|No Cat. 14.681 @ 94.80
2002 Dark Cherry Grand Prix GTP Supercharged & Intercooled
12.084 @ 114.38 w/1.743 60', 315.6whp, Fastest Stock Cam M90 GTP!
NOW XP CAMMED, 340.6whp with XP, stock heads, Gen 3 M90, 11.984 @ 115.84 w/1.750 60'!
Most HP Stock Heads Gen 3 M90 GTP!
2004 Red Monte SS Supercharged K&N|3.4 Pulley|1.9'*|180*stat|41919 plugs|3" dp|No cat/ubend|DHP|Shift Kit. 14.2 @ 98
GOT BOOST??? Friends dont let friends drive stock!